What are the solutions to go from Beijing to the jinshanling section?

I read that at Dongzhimen Wai station there is a single bus that leaves at 8 o'clock but only on weekends and holidays.

While at Wangjing West Station there are buses every hour starting at 7 but I didn't understand the route these buses take. I read that after an hour and a half they drop you off at a rest area and from there you take a shuttle bus to the wall. Would it be possible to know what is the exact route regarding this choice?

Thanks a lot.