Proper ground prep is the key. Gaps can be filled with sand to make it perfectly smooth. We actually used a checkerboard with sand in part of my lawn and it filled in within two months.
Thank you for the useful video. This video is from 10 months ago. Did you place sods in September last year? I wanted to know if placing bermuda sods in September will be ok rather than doing in March/April. I live in Central Texas.