Hello Mike,
I have kept Salamandra successfully, in southern England, using exterior quality, 8 x 4 foot plywood sheets for outdoor enclosures.
My method is to dig a hole, on the North facing side of the garden, 4 foot square, and 2 foot deep, and sink a ply box into it, infilling with bricks/rocks/stones, to create a frost free hibernacula, for brumation. Finish with a covering of soil, then dry leaves, rotting softwood logs, ferns, moss etc. I find that a black plastic paint "roller tray", (obtainable from all good DIY stores),
sunken into the soil, provides a shallow container for adult salamanders to produce their young, without drowning themselves. Finally cover the enclosure with a mesh lid, to protect them from vermin.
As for seeing the inhabitants......I suggest you brush up on your "Raindance".