Typically on VOR approaches you have to first overfly the VOR and then make a “U-turn” like shown below:
My question is how do you know when to start the left turn to 12 degrees? Is the minimum altitude at 3600 feet when I start my turn to 192 degrees?
You can start the procedure turn any time after the VOR but you have to remain within 10 miles of the VOR so don’t start it too late. You have to stay above 3600 feet during the turn. You can descend to 1600 feet after you have completed the turn and are established on the final approach course.
In addition to Mike’s good answer, you don’t have to descend to 3600 ft to start the outbound (012) leg of the procedure turn, you can be descending from above 4000 to 3600. You need to stay within 10 nm of VOR but also you want to give yourself a little room for the segment where you intercept the inbound on the VOR radial (237 To VOR) to become comfortably established on the radial and not be zig zagging as you cross the VOR.
Don’t feel you have to fly via the overhead. You can also join the arc via the initial approach fixes and could possibly even go direct RIXAE for a straight in approach.