What do you do when you download a game but it dosent show up on ps3?

If you download a game on your PS3 but it doesn't show up, first ensure that the download completed successfully. Check the "Game" section on the XMB (cross-media bar) to see if the game is listed there. If it's not, try restarting your console, as this can sometimes refresh the system. Additionally, verify that the game is compatible with your PS3 model and that you are looking in the correct folder (like the "Game Data Utility" for installed games).