Porcelain Mosaic to Shower Area

[meowork]

Morning
I'm planning on tiling the shower area with small porcelain mosaic tiles (several on backing sheet).
I have plastered walls so unsure how to treat/prepare the plaster prior to applying waterproof adhesive and tiles.
Is their a sealant for this or do I use something like PVA?.
Appreciate advice.
Many thanks.

 

[Mr Rusty]

I'm planning on tiling the shower area with small porcelain mosaic tiles

You must like cleaning. All those grout lines to keep sparkling! Small mosaics really are a b'stad to keep clean in a shower.

If you insist on doing this use a shower tanking kit on the walls first.