Are you talking cleat set up? You shouldn’t have to mark anything. Set the cleat pretty much centered left to right, hopefully your shoe has graduations that show the center line. When the shoe is moved inwards, your ankle should just miss the crank. You can tweak it a bit later if you aren’t digging how far you have to twist out to unclip or if your foot naturally hangs a bit more inward than most.
For front to back also start in the middle. The goal is to have the ball of your foot over the spindle. You can clip in, see where the ball of your foot is, then take the shoe off while still clipped in and eyeball it off the bike to see if you need to go front or back. If you start having some new knee pain after a few rides you may want to move them aft a bit.
A good shop will set this up for you. I just picked up some winter shoes from Halters recently and Chris slapped some new cleats on for me in the shop. When i got home I had to do a minor tweak on my left cleat then tighten them down to my preferred cleat torque. (German tight) Besides the small adjustment I made before my first ride they were set up perfectly in the shop. I am sure if I had my bike in the shop I would have left there with them set 100%.
Another plug: These winter shoes were easily the best bike related gear I have bought since my first clipless pedals. (onza HO's, 1993) My feet have never been so comfortable in the winter. Thanks jdog and Halters crew.
I think I still have those onza's laying around, and eleventy sets of elastomers. I really need to clean out my garage.