Start at 25 yards
Fire 3 rounds, from a steady rest.
Adjust the scope, remembering that a one inch "miss" at 25 yards is the equivalent of a 4 inch miss at 100 yards. In other words, to move the point of impact (POI) one inch on a 25 yard target will require 16 clicks, if your scope adjustments are calibrated for 1/4 inch per click at 100 yards.
After firing 3 rounds, initially, determine the center of the group, then adjust to bring that center in line with the center of your target. If your 3 round "group" is overly large (greater than 2 inches at 25 yards), start over and shoot a new 3 round group.
Use a small aiming point. I put a 1/4 inch diameter blaze orange "sticker" in the middle of whatever target I am using. Typically a target may have a one inch, or even larger center ring. "Aim small, miss small" is the axiom.
If your POI is off in both elevation and windage, work with only windage until you get it centered, then work on elevation with additional 3 round groups. Trying to do both at the same time only complicates things, especially with newbies.
Hope this helps you at least get started with the process. There can be a lot more to it, but it may also be just this simple.
When you have both the windage and elevation "spot on" at 25 yards, put up a target at 100 yards and start the process over.
Remember to "aim small", use only 3 round groups of 2 inches or less size, and adjust only one aspect (either windage or elevation) at a time.
Good luck.