Newbie - Grid with 3 cells

Hi and welcome

You don’t merge cells, You pdf build Divs on the cell’s Grid. Create A 4 cell grid and on top of that grid create 3 divs, one div of 2 cells and another 2 divs of 1 cell each.

https://www.loom.com/share/391b25b645874daca5ebb43f22d4ce1f