how to register manually?

okay...I've gone around to different peoples comments about how to registered manually but i can t seem to find what I need. I click onto my unity on my desktop and it simply comes up with registration. so i tried the internet way but nothing:(( so I tried the manual way but I don't know what to do i saved the license and then tried to read it by click the second button and then i clicked on the saved file but that didn't work cause it said something like "can't open this folder due to into not have the license documents". Or something like that.

Okay so all i really want to from you guys is not to give me a link to another, I just want to you to give me easy steps to doing it:)) PLEASE PLEASE PLEASE!!

P.S you guys are awesome:D