As Ryan says, its all pretty easy to navigate from Rhyslyn car park. It is a good idea to print off a map fromthat site as well. As you have quite a few hours up at Afan, let me suggest an alternative route:
Do the wall climb, you will go through 3 gated trails with fireroads in between. At the top, turn right along the fireroad and head for Whytes (signposted as W2) on the link road. When you get to Energy, do that then follow the diversion signs to the Skyline descent. When you get to the bottom, have a break at Glyncorrwg centre where they have a cafe/ shop. Then do Whytes climb, black run/windy point/both, then return over same link road to finish off on the wall descents, more or less where you started at Rhyslyn.
Just saw the weather forecast and it looks wet, Take a spare pair of shorts for the train home, you’ll be muddy!