ᐅ Idea collection for the surface of a garden staircase!

Hello everyone,

Attached is a photo of a staircase I built into a slope last year. This staircase is now going to be covered with various tiles arranged in a mosaic style. We have simply broken different tiles and laid them out as a trial. I’m not exactly sure what the best approach is. Should I apply tile adhesive to one step and press the tile pieces into it? Or should I apply tile adhesive to each small tile piece and then stick it onto the staircase? Has anyone done something similar by any chance? I’m also uncertain about how to proceed with the grout. The surface isn’t particularly even. Maybe someone has an idea...

Thanks and best regards

Stefan