The pattern uses US terminology. I have used light worsted yarn to crochet the Queen's Guard and a 3.5mm (E-4) hook.
The pattern uses:-
Crocheting in the round
In addition to normal crochet supplies you will need a split ring, embroidery thread and beads. This is the perfect pattern for using up your stash as the guard 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 children.