You broke , or maybe forgot a tile leveling base clip, Now what? here is the solution

From a channel Lumen includes in full: saldibs: a professional tile setter's detailed tiling instruction (layout, waterproofing, mortar, cutting, showers), praised on r/HomeImprovement for doing it the right way.

A 10-minute video from Sal DiBlasi's catalogue; the title names its topic.

Video by Sal DiBlasi, played through YouTube's embedded player.