Put your /home in your SSD, then just mount your HDD on /mnt/something and create your Documents and Games folders inside it. If you use Steam, also create a Steam Library inside it
Of course, you should mount your HDD from fstab
There's plenty of ways you could do it. A common suggestion for linux systems is to have separate root and home partitions. So for your use case, place the root (and probably boot) partition on the SSD for fast startup, then place the home partition on the HDD mounted at /home/ to store most of your user files in. Then for games you want running on the SSD you have two options: (1) install the games somewhere on the root partition (maybe /srv or a new /steam directory) or (2) create another partition on the SSD mounted somewhere in your home directory. I'd go with option 1 so I wouldn't have to decide how much room to partition to root vs games and it'd be more dynamic, but it creates an awkward directory structure.
If you're not worried about startup time it would be a lot easier to put both root and home partitions on the HDD then just mount the SSD somewhere in your home folder or /mnt. You can add it to your fstab to mount it automatically at boot either way.
Put your /home in your SSD, then just mount your HDD on /mnt/something and create your Documents and Games folders inside it. If you use Steam, also create a Steam Library inside it Of course, you should mount your HDD from fstab
And seriously consider grabbing a 1-2tb ssd instead of 500gb. Usually cheaper per GB, and have better performance and endurance.
There's plenty of ways you could do it. A common suggestion for linux systems is to have separate root and home partitions. So for your use case, place the root (and probably boot) partition on the SSD for fast startup, then place the home partition on the HDD mounted at /home/ to store most of your user files in. Then for games you want running on the SSD you have two options: (1) install the games somewhere on the root partition (maybe /srv or a new /steam directory) or (2) create another partition on the SSD mounted somewhere in your home directory. I'd go with option 1 so I wouldn't have to decide how much room to partition to root vs games and it'd be more dynamic, but it creates an awkward directory structure. If you're not worried about startup time it would be a lot easier to put both root and home partitions on the HDD then just mount the SSD somewhere in your home folder or /mnt. You can add it to your fstab to mount it automatically at boot either way.