When you install a game, the game appears on the Switch home menu, and you can launch it from there as long as you're running CFW. It's also recommended that you install the latest game update NSP for whichever game you're installing.so when games are installed do you have to play with a program or just adds it self to main game desk top still installing a game
Tinfoil has had blocks on a lot of common NSP files, like "junk DLC" blocks. These files are often times the only NSP files available for specific DLC, so they couldn't be installed over a Tinfoil Shop, and you would have to use something like TinWoo in order to be able to install that DLC.I've never used a shop, only ever over USB. I've maybe been fortunate/lucky with Tinfoil/Nut combination, its worked flawlessly when compared to NS-USB Loader, Goldleaf etc etc.
For this reason and others, TinWoo is generally recommended for installing manually-downloaded NSP files, and Tinfoil is generally recommended only for Tinfoil Shops.