First go to this website www.technicpack.net/tekkit/
Now click on "Download technic launcher"
Third click you're operating system Mac/Windows
Then go to youre downloads folder put technic launcher on you're dock or screen or just open it "if its in a zip file unzip and open it"
Now just put in youre account and select the kind of game "tekkit, tehcnic pack, yog box, vannila, exc"

This is also a good thing to do if you have the problem Done loading with you're normal minecraft and you cant fix it