What is patt=moss stitch
what PLY is sport or worsted weight yarn?
Many thanks for all help received.

Moss stitch can have a somewhat loose definition. This is a video for what I think of as moss stitch but sometimes your pattern may specify differently.

Ply isn’t used so much in the US anymore because it can be an unreliable measure of yarn weight. Roving and lace yarn can be single ply with big differences is gauge.
Here’s a table that shows sport as 5 ply and ww as 10 ply.

Gauge/tension is more realistic than ply.