First, thank you guys for trying to help me. :D
Okay, I saved a new game (created new sims, etc), and I have now 'Load' button. This game saved as slot_0000002. in the 'saves' folder.
I moved my original slot_00000001 (what I really want to play, its my previous save what I wrote that moved copied etc etc.) to this 'saves' folder, near the the new, slot_2 file.
I found a button 'Recover save', but there is no way to load the slot_1, although I moved it to the right place.
The makers should edit the game so that you can insert/pull the file into the game. xD
Oh, I play on iMac 2017.