Gary was mostly correct, but let me add to his 🙂
2) Landing Gear Lever must be in Off or Down position for autobreak to work
4) Profile mode is a very rudimentary VNAV mode, but the plane is old so it doesn´t always work the best. This was/is the same in real life. Most airlines didn´t even use profile mode for that reason.
I recomment you to watch our new or returning to airlines series on youtube. There you will learn everything you need 🙂
https://www.youtube.com/playlist?list=PLzeFYXw62MgZWG518Qe3aqz_9wLIT_aRa