I worked as an OR scrub tech for many yrs prior to becoming a nurse. You should be able to look at/borrow books with pictures of instruments/what type of surgery are they used for etc....either from dept head or from the instrument room. Also, they should have a count sheet for each set of instruments that may help some. It's all memory,lol. Don't get overwhelmed as it is not as bad as it seems. I know at first, it's like, "how the heck will I learn all of these".....but you'll do it. LIke with forceps, as long as you know the difference between toothed vs smooth, the difference between snaps vs allises etc.......
Once you start scrubbing on diff. surgeries, you will be able to anticipate what they will need, lol, many times you will give the surgeon what he/she wants before they even know. Wow, I didn't realize how much I missed the O.R. Many say, that once you worked in O.R. you'll always come back to it. That may be true. Where I live they don't hire lpn's in O.R. and I am about a yr away from getting my RN.
Anyways, back to subject....memorize, memorize, memorize........lol