easy question

[GunnerySargeantBeckett]

How do you put a way point for a specific unit

[Seven]

select the unit, press F4 and click on the map where you want the waypoint.

Have a look at this page with nice tutorials; there's beginners tutorials for these things too
http://www.ofpec.com/ed_depot/tutes.htm

have fun 

[THobson]

Waypoints are for groups, but a unit on its own is also a group so you can give a single unit a set of waypoints.  What you cannot do is have a group of several units but give only one of them a waypoint.