since you appear to have no idea what you're doing i'm going to give you the general gist of what to do
YOU MUST HAVE THE PROFESSIONAL OR ENTERPRISE EDITION OF WINDOWS IN ORDER TO DO THIS. There are hacks to do it on Home Edition or Home Premium, but legitimately speaking, you must indeed own one of the versions above to do this.
Select "Remote settings" under Computer in Control Panel

ensure "Allow users to connect remotely to this computer" is enabled
click "select remote users"

click "add"

type "Computername\Username" for whatever user will be logged in
click ok
you're done