Storage is going crazy?

I have a 100GB ssd and a 1TB Hdd. Now I downloaded various game launcher yesterday, as well as Rainbow Six Siege and Minecraft. Apparently, both ran on the SSD (had no visible option to select the storage location). Now I have the problem that the local memory is full (100GB) and I can therefore no longer download anything. My question, how can I possibly upload it to the Hdd? Or how can I upload more games to the Hdd - Apparently the local memory has to get empty first.

I can only recommend TreeSize. Displays everything sorted by size on the disk and reveals the memory guzzlers. Is absolutely freeware, not even registration required.

An SSD with 100/120 GB is best disposed of. It is prepackaged.