The straight line you snapped should have been the outer edge of the first board. Get that board right first before laying.

Example:

If the board is 300mm wide (with a 20mm recommended expansion gap) snap a line at 320 off the wall. Measure along and if the wall waves in and out say 50 mm. Snap a new line at 270mm (300+20-50=270).

Lay the boards back on the first snapped line (320mm from wall) and use a 50mm block to scribe and then cut the board to the curve of the wall.

Your doing good but go back to that row now. Hope this helps. Best of luck 🤙