Every store handles 4x4s differently, so I'll tell you how my store does them.
1. Superzone the aisle.
2. Check for missing labels and signs. Print if necessary.
3. Research any outs* and apply gray dots as needed. If you have the product in the backroom, drop a fill batch.
4. Replace any missing or broken fixtures, sign holders, and label strip holders. If you don't know where to find them in your fixture room, partner with a plano TM or your friendly neighborhood signing ninja.
*If an item is discontinued and out of stock, cover or remove the price label. Ask a leader if they want you to flex a different item in that location. If you do, make sure you Store Tie the item in the aisle (ask a leader which section to use, i.e. 91, 92, etc.) and print a label (and sign if necessary).
When the 4x4 process first rolled out, we had to fill out a sheet for each aisle. We would check off the areas in which we had to fix issues and note any problems that required follow-up. The sheets would go into a binder and supposedly be audited by the ETLs. Nowadays, we don't use the forms and just fix whatever we can in between assisting guests and back-up cashing.
The sheet you fill out may just be a templated chart which breaks down what info your leaders want for your assigned aisle(s). If not, ask them what they'd like to read.