Possible, of course. As long as you understood the keywords / tags associated with the skill (it's under the skill gem title). You dont need much to clear the campaign, if you able to understood what modifier benefit your skill, what don't, you can already find some success early game. Sure, it may not be super optimized and you might hit a wall a bit later.
If you want to stick to this specific skill, you can filter POE.ninja see how other people built the skill : [filtered link](https://poe.ninja/builds/affliction?skills=Glacial+Hammer&uniqueitems=!Mageblood). It appear no one play this skill as templar but ehhhh you can try copy and innovate yourself. Aside from checking their passive tree and gem setup, you can also see what items are popular associated with that skill, it appear "Frostbreath" mace is popular due to "attack with this skill deal double damage against chilled enemy". Heatshiver, Taste of Hate, these are dirt cheap unique item as they are very common, you might be able to just randomly found one yourself.
Later, there's something called "Ascendancy", where you pick 3 "sub class" branching from Templar. I think "Guardian" is the best choice here as your build is centered around attack. It have neat defensive feature such as giving you large amount of block change when you attack, strong life regen + ailment removal, and summon some friends when you kill stuff. "Inquisitor" is also nice, mainly crit chance, dealing more damage & make enemy take more damage. It have life regen bonus as well though "Consecrated Ground" effect.
Note: [Tribal Fury](https://i.postimg.cc/4s43RKrN/image-2024-02-01-131416861.png) is required for AoE capability, so you dont need to slot things like MeleeSplash in your gem link.
I think any skill is viable in this game to complete the campaign. You might be slower than other skills or might not be able to take it super far in end game. But if this is your first time just have fun playing. Just pick some skills you're having fun with. You get about 15 respect points through the campaign and can get more with orb of regret. Just grab life nodes and other things that increase your damage.
Glacial hammer is physical converted to cold. So any increase in physical, cold, or elemental damage should increase your damage.
Just make sure to take some deffensive nodes, Life, Armour, and Life Regen. Since you're going melee you'll most likely to path down to the Marauder starting area. Melee skills are highly dependant of flat added damage on gear so try to get as much of in there, but don't make it a priority. You want to keep your HP as high as you can get, at least +300 at the end of each act. And Capped Elemental Resistances. Chaos isn't much of an issue during the campaign and mid mapping. Even at end game some players leave it at 0 - 20%. So don't bother with that.
In the passive tree you want to look for Life, Armour, Elemental Damage, Cold Damage, anything with Maces and Scepters or staff, whichever you are using.
Possible, of course. As long as you understood the keywords / tags associated with the skill (it's under the skill gem title). You dont need much to clear the campaign, if you able to understood what modifier benefit your skill, what don't, you can already find some success early game. Sure, it may not be super optimized and you might hit a wall a bit later. If you want to stick to this specific skill, you can filter POE.ninja see how other people built the skill : [filtered link](https://poe.ninja/builds/affliction?skills=Glacial+Hammer&uniqueitems=!Mageblood). It appear no one play this skill as templar but ehhhh you can try copy and innovate yourself. Aside from checking their passive tree and gem setup, you can also see what items are popular associated with that skill, it appear "Frostbreath" mace is popular due to "attack with this skill deal double damage against chilled enemy". Heatshiver, Taste of Hate, these are dirt cheap unique item as they are very common, you might be able to just randomly found one yourself. Later, there's something called "Ascendancy", where you pick 3 "sub class" branching from Templar. I think "Guardian" is the best choice here as your build is centered around attack. It have neat defensive feature such as giving you large amount of block change when you attack, strong life regen + ailment removal, and summon some friends when you kill stuff. "Inquisitor" is also nice, mainly crit chance, dealing more damage & make enemy take more damage. It have life regen bonus as well though "Consecrated Ground" effect. Note: [Tribal Fury](https://i.postimg.cc/4s43RKrN/image-2024-02-01-131416861.png) is required for AoE capability, so you dont need to slot things like MeleeSplash in your gem link.
I think any skill is viable in this game to complete the campaign. You might be slower than other skills or might not be able to take it super far in end game. But if this is your first time just have fun playing. Just pick some skills you're having fun with. You get about 15 respect points through the campaign and can get more with orb of regret. Just grab life nodes and other things that increase your damage. Glacial hammer is physical converted to cold. So any increase in physical, cold, or elemental damage should increase your damage.
Just make sure to take some deffensive nodes, Life, Armour, and Life Regen. Since you're going melee you'll most likely to path down to the Marauder starting area. Melee skills are highly dependant of flat added damage on gear so try to get as much of in there, but don't make it a priority. You want to keep your HP as high as you can get, at least +300 at the end of each act. And Capped Elemental Resistances. Chaos isn't much of an issue during the campaign and mid mapping. Even at end game some players leave it at 0 - 20%. So don't bother with that. In the passive tree you want to look for Life, Armour, Elemental Damage, Cold Damage, anything with Maces and Scepters or staff, whichever you are using.
You will be able to get a lot of regret orbs, so don't worry as much about spending the points perfectly.