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:-
Crocheting in the round
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.
Due to small parts the finished key chain is not suitable for young children.