What do I need to know about running Amazon Ads for the first time? Is there an ideal time/day? Do I need to have a certain amount of reviews on my book before advertising?

I just published two new workbooks on Amazon KDP at the beginning of June 2026. I originally had no issues with uploading and publishing my original manuscript. Since my launch I went back to update my manuscript to include a link for a review, the ISBN number and I fixed a couple typos. I'm getting extremely frustrated because I have edited and re-uploaded over 5 times now and I cannot get approved. The email says "Your file contains insufficient bleed." I have redone my margins, moved text and images around and I even did a live chat with an amazon kdp agent and still cannot get approval. The agent told me to resize my original file (I created it in canva) from and 8.5' by 11' to 8.62 to 11.25 which I did and still did not get approved. I am at a loss. It's very frustrating because it was approved the first time and now it's not. Please help.