This is a step by step tutorial for join as you go construction.
I would say it would be perfect for an adventurous beginner who was keen to learn new techniques!
I have used Scheepjes Metropolis yarn but any fingering weight yarn will do. I have used the following amounts:
Yarn A - 400m
Yarn B - 400m
Yarns C, D & E approx 50m of each
Colour names and codes for the yarns I have used are on my blog.

The pattern can easily be adapted to any cushion size. I have used an 18” cushion pad for mine.