How do I lay sheet tiles so they are flat

I have 2" octagon ceramic tiles on backing roughly 12" square. My concern is that when I lay the flexible tile sheet onto the notch-trowled adhesive, and apply some pressure to set it, some parts of the sheet may sink deeper into the adhesive more than other parts resulting in a "wavy" floor. I assume that a minimum amount of adhesive applied with a 1/8" notched trowel and not buttering the back of the sheet may be part of the solution. How is a level surface accomplished?

You end up with a flat surface by starting with a flat substrate.

Set the sheets into the thin set mortar, then tap the tiles with a rubber grout float.

Jaz

Generally back-buttering mosaic sheets is a no-no. The use of a proper trowel notch will guarantee a proper bond and eliminate purge.

If the correct trowel is used "some parts of the sheet" WILL NOT sink deeper if you use Jaz' method above. A laminate roller can also be used to embed the sheets in the mortar. Of course if the substrate isn't plane the tiles won't be plane either.

When saying "adhesive" - I hope you are talking about thinset mortar adhesive!

I appreciate the the advice. It's a great help for a novice like me. And yes, I do mean thin-set mortar.