As far as specific AP controls, look at the image in the post above. There are (5) specific controls you only need to be concerned with. Theflight director switch,  heading bug on the HSI (so you can set the heading you want the AP to fly), The overhead VOR selector, and items 4 and 5 in the image above. Lets say you are about to take off...first set the flight director on the front panel left of the yoke as you taxi to the active. You will probably be flying ATC vectors to get you on course, so intitially you will be flying in heading track mode, so set item 5 in the above image to VOR, set heading to manual (item 4). When you take off, turn the AP on, the turn the heading bug to desired heading. You can control your descent, ascent rates eith the pitch trim wheels next to the AP panel. When you are on course, quickly turn AP off, set heading hold to normal, item number 4 to tacan, then turn the AP back on. Then it will track your MSFS flight plan.