I don't know your circumstances nor the machining tasks you'll need to accomplish but I have to say, with all due respect, that your questions are so very basic that you shouldn't even approach the mill until you've done some reading. The engagement of the drive system in the step-pulley mills is so very basic that your questions (while good that you did ask) means your inexperience could lead to damage and/or injury to yourself and/or the machine. I'm not knocking you, we all were born without knowing, I'm more than a little surprised that a university would be so casual as to allow someone to operate machinery without proven and demonstrated experience. The very fact that you've been appointed as "manager" is another matter I won't go into. The point of my reply is not to point up your inexperience or to question the "wisdom" of a higher learning center. My point is that I've seen many bad things happen by people that were supposed to be skilled tradesmen. Damaged machinery and ruined parts/tooling was the least of the incidents. There were times I had to take people to the ER, and worse due to inexperience. All it takes is one moment to occur and you may not see it coming. Your experience with CNC will likely not be comprehensive nor relevant enough to transfer to manual machinery, they are different animals with different pitfalls. There's only a couple of reasons for the mill to have been left in neutral (if it was) so it may very well be that somebody is yanking your chain. The reason is not important, what is important is that if you don't know how to change the spindle speed on a high/low step pulley drive then there's a real good chance that you'll commit the error too many of us have heard before. If you don't know how to change the belt to a different pulley you'll likely pinch or break a finger. If you don't know how to positively engage the high/low drive then sooner or later you'll turn on the machine and a gawd-awful noise will loudly announce to all within earshot that the FNG should have done more reading. Rather than discourage your ambition I would encourage you to be better prepared by seeking out advice either by reading or asking someone in the shop that DOES know. There's no shame in not knowing but there is in not asking. To address your original post, I always double check for positive engagement before I even think of putting my hand near the ON/OFF switch. If I haven't heard the characteristic engagement noise I'll even take it out of gear and put it back in just to ensure that it is. Be careful, machines are dangerous and you're just another material to be cut. This is a good site and some very knowledgeable people here (except me...) that can provide a wealth of information/experience for you AFTER you've done your own searching for information. Good luck.