Before you embark on the realization of your entire bathroom, here is the procedure for a small fresco ... which will get you started!
On a 180 g sheet of paper, draw your pencil drawing.
With the tiler pliers, cut tesserae and store them in boxes according to their colors.
Spread white glue on a small part of the drawing and start installing your tesserae, colored side on the glue.
Continue your entire fresco this way.
Coat with thin-set mortar and the notched spatula the part of the wall receiving the fresco.
Position the back of your fresco on the mortar and smooth with a painter's roller.
After the mortar has dried, peel off the paper, moistening it with a sponge.
When the paper is completely gone, proceed with grouting. For this, you can use a special ready-to-use joint paste (which exists in different shades) or make it yourself by dyeing it with universal dyes.