In Diablo 3 for the PC, once you hit a certain point in the game you’ll start to see more socketed items that you can put gems into, but how do you place gems into these sockets?
It’s actually quite simple, in that you just need to click on the gem and drag it onto your socketed item. It doesn’t even ask you to verify that you want to socket that item, it just places it in the first available socket.
Be careful when socketing items however, since it costs money to remove sockets from an item at the Jeweler.