Nice shots. That old tractor is in pretty decent shape. Could use a wash and wax, but that can wait.
Looks to me like you have one remote outlet. One port is for fluid going to the implement, the other is for the fluid returning. Somewhere (it's usually by the three point lift lever) there's a control for the remote. A remote like this can be used to extend and contact a hydraulic cylinder on an implement, to raise and lower travel wheels on a disc for example, or adjust the angle of a back blade. If you don't have anything with a hydraulic cylinder, you can make or buy (Brian at FitRite hydraulics makes great stuff) a cylinder which replaces your top link. This allows you to adjust the pitch of anything you've got on the three point, which is real handy.
Good for you for not being afraid to tear into stuff. Old tractors like this one aren't exactly Swiss watches, so it's a great learning opportunity. Getting the manuals is a great idea.