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

In addition to normal crochet supplies you will need a split ring. This is the perfect pattern for using up your stash as the Sammy uses less than 25g of each color.

This pattern would suit someone with an intermediate skill level.

The finished Sheep key chain is 3” 1/2 inches high including the key ring and 2” 1/4 inches wide.

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