have opened a hole in the basement wall to install a door (a door has previously been there).
the problem is how to attach the bricks/leca blocks to the porous and incredibly uneven wall that seems to consist of coarse stone and some porous cement-like substance.
see attached images, on the right you can also see the last concrete blocks that need to be removed.
also, tips on how to attach the door frame to the wall blocks in a good way are desired.