"Could you further explain how the shimming works"
OK so a few additional points that are key.
1. I AM DUMB.
Your scope elevation has a knob that goes from 0.0 to something. My something is 5.0. If I want to go up 12.2. From my zero, I do 2 complete laps and then 2.2 more. If you want to go to 7.2.... it looks the same. BUT you need to know that you have to do a complete turn back down. Once you go past the 0 a couple times you may forget. For this reason. I always go back to my zero. If you never forget, you can skip the step. BUT will you remember with that " sheep at 700, NOT WAIT huge sheep at 250 " or in a contest?
2. 1/10s COUNT at DISTANCE.
The scope comes with a defined range of say 25mil adjustment. But when you zero you will notice that you may already on 14.x. That means that you will only have 10.x left to adjust.... This will probably not be enough. You will want to use that angled base to get your scope set somewhere lower in it's absolute range in order to dial out the dope you need. YES YES you can dial out 10 and hold 5 more, but you are just guessing/gauging the increments.
3. DEER ARE FREAKING HUGE
If you are hunting at distance, holdover is probably fine. All my experience is attempting to shoot very small targets for very small groups at as long of distance as the range will support.
OK so the question...
When you buy a new scope it comes with a handful of c shaped metal shims. If you remove your scope cap, you can see that there is a tube that gets longer and shorter as your turn the knob. The hidden end is attached to the optics and ultimately appear to move your reticle.
If you add shims on the tube under the knob, then the knob cannot turn down as far. The goal is to add shims until you use up 99% of the free space under the knob for your chosen 0. Then you can quickly turn the knob down until it stops and you will be close to your 0. If you did it 100% you would be at your 0....
... but I mentioned before that I leave a couple clicks extra, because if I happen to be shooting at my 100 yard zero and switch to a slower ammo or a huge headwind, I may need a couple clicks. I dislike holdovers, but I HATE holdunders.
To perfect the "close to 0" that you achieve by quickly turning all the way down, you realign your cap so that when you reassemble and tighten it, it has the 0.0 on the line.
I hope this helps further. Ask any more specific question that you have and I can give my opinion / take.