Create a topic and ask here, people are keen to help? 
Here’s a couple of non-intuitive things on the C4J to kick off:
-
There is no auto-throttle on the Citation even though it looks like it on the AP. What you can do is set a speed on the autopilot and the system adjusts climb etc pitch to match it. The physical throttle has indents for cruise/climb etc to set at. It sort of works.
-
To capture the ILS, switch from GPS to VOR nav input. You can use the top left NAV toggle here (marked beautifully as ‘1’) -
…or via the PFD Menu. You should get a pink FD lines go green.
-
You can zoom in/out the main display ARC using the fake toggle here, marked (2).
-
VNAV features on the stock aircraft is sort of non-existent, and it’s very handy on a fast jet like this. The mod here is better in practically every way. If you like the type then it’s probably worth just using the mod, as it has a lot of the bugs fixed up out of the gate.