The pattern uses US terminology. I have used light worsted yarn to crochet the Russian Doll and a 3.5mm (E-4) hook.
The pattern uses:-
Magic ring
Single Crochet
Slip Stitch
Crocheting in the round
Chains
Changing color
Crocheting in back loop only

In addition to normal crochet supplies you will need a split ring, 3mm Black beads, felt and embroidery threads. This is the perfect pattern for using up your stash as the Russian Doll uses less than 25g of each color.

This pattern would suit someone with an intermediate skill level.

The finished Russian Doll key chain is 4 1/2” inches high including the key ring, 1” 1/2 inches wide.

Due to small parts the finished key chain is not suitable for young children.