Also watch this video. See how I can easily control the cylinder and the hole in the side of it? The other guy is going to struggle to do that. Also notice that he controlled the depth of his hole by dimensioning his point 18mm out from the axis (he wanted 7mm deep, and it's a 25mm radius cylinder)? Well, what if he changes the cylinder diameter? Will the hole stay 7mm deep? No. He's going to have to do his math again and also change the hole depth to match the new cylinder diameter. Instead, I controlled the 7mm depth directly from the outside, so no matter what diameter I change the cylinder to, the hole goes with it at the right depth.
These are the simple sorts of things that you've got to think about to be a good modeler. Think about what you might want to change, and then about which elements should be dependent upon, or referenced to, which other elements. In this case, the depth of the hole (one M&M depth plus a tolerance) should be dependent on the outside of the cylinder, not the axis of it. There may be cases where you want the depth of a hole referenced from the axis, but it doesn't make sense in this case, right?
Also you might have noticed in my previous video that the arc defining the hole's bottom was blue in my sketch. That's because I started with a 3-point circle and then trimmed most of it away. Before I started this second video, I had changed it to a tangent arc and constrained it properly, so it's black now. You'll want to try to fully define everything in your sketches such that they turn black. There are a few bugs where things will show blue even after they are fully and properly constrained, but don't let that bother you. Learn how to fully and properly constrained your sketch elements as a habit. It will save you lots of frustration in the future.
Why do I feel like I'm teaching you a lot more than that video guy did? Just want you to see what good parametric practices allow for. Once you learn enough, you'll be able to learn more even faster, because you'll be able to watch videos like his and pick out the useful info from the crap. Anyway here is my second video:
A link to it, just in case the forum gives me trouble:
https://knowledge.autodesk.com/community/screencast/cfb6a17b-35d3-4fba-bc7c-50cf00e1229d