This pattern is written for Blanket Yarn - #6 Super Bulky
and it makes a small Bee - The yellow bee shows the size.

However, you can make it with the yarn & hook of your choice.
The Bee will just be smaller if you use a lighter weight yarn with a smaller hook - The purple bee shows the size with a #4 Worsted Weight yarn and a 4.5mm hook.

This pattern is considered a Beginner pattern.