Don't beat yourself up for not knowing how these work if you're just getting started in commercial work-none of us are born knowing this stuff. I like the fact that you are taking initiative to find answers-definitely the sign of a good tech. Anyone that thinks they've seen/know it all just hasn't been doing this long enough. Get used to not knowing-there are a million ways to do everything-even though ultimately we're trying to do the same things.
Having said that, as klrogers said-get the books from Trane on their MicroControls and Ignition and Combustion-you might find them here or somewhere on the net, if not, you can get hardcopies (which I have, and tried to upload here for you-but wouldn't go through).
The Voyager has 2 test terminals-literally called "Test 1" and "Test 2", on the main terminal strip. Take a jumper wire (or a pair of wire strippers/quarter-whatever), and jump out test 1/test2 for 2-3 seconds. Don't leave the jumper on-this test is sequential. The first test brings on the indoor fan. After you see the fan come on, jump out test1/test2 again-don't forget, jump it out for 2-3 seconds, then take the jumper off for 3-5 seconds. The next test is economizer. After that is cool 1-economizer close, then cool 2 -mechanical cooling, then heat 1, heat 2. When you use the test mode, bear in mind certain things are supposed to happen at given times.; When you get to the heat test, the combustion blower has to energize, all limits have to be closed, and the ignitor has to energize. If the combustion blower does not energize when it should-look to find out why...
Our job is to figure out WHAT is supposed to happen WHEN-and WHY it's not. Hope this helps. Word to the wise-read everything you can get your hands on-when you know it-you own it!