What to do with this subflooring over concrete before lying down Vinyl
Novice here. I have cutout a lil area of carpet by my front door. I want to laydown a vinyl flooring sheet to make it easy to clean since my front door is my main "guest door". I have a concrete slab ranch. On top of the concrete (as pictured) is this subflooring (not sure if thats the right word).
My question is, between each square is a gap that I know I can't just leave it how it is with thin vinyl. What exactly are my options here. I assume that the 2 that I have are filling the gaps with some kinda filler, or removing the squares that are glued on. I'm open to any idea.