Once I had glued the first layer of foamcore to my baseboard, I marked the 8cm x 8cm grid on it using a long ruler and a Sharpie pen.
I did this to give me some idea what the end result would look like. I already had a rough plan of the grid I wanted to create ...
... and having a full-sized grid to look at helped me to finalise my ideas as to where various terrain features would go.
The board is intended to be used to fight battles using the ShamBattle/Portable Wargame hybrid rules that I play-tested back in November 2023.
I then began the process of gluing the second layer of foamcore on top of the first layer. Whereas the first layer had been glued on landscape (i.e. the longer edge of the A4 sheet of foamcore was glued parallel with the longer edge of the baseboard), the second was glued on in portrait (i.e. the shorter edge of the A4 sheet of foamcore was glued parallel to the longer edge of the baseboard), thus:
You will note that I cut the outline of the river into the foamcore sheets as I glued them in place. (I also made a small mistake when doing this and made the river end in the wrong grid square! I will need to amend my rough plan for the finished layout accordingly.)
I also marked the 8cm x 8cm grid onto the top layer of foamcore as I went along as I thought that this would be of assistance at the next stage of the baseboard's development.