There is an error in the printed pattern, but it’s just a numbering error. Round 20 is a repeat of Round 16, then Round 21 starts with the “Ch 1, Fpdc…” right afterwards.

I’ve added pictures of Rounds 15, 17, and 19 since there was some confusion for some crocheters about these rounds. Hopefully they’ll help! Let me know if you have any other trouble with this pattern.

EDITED TO ADD:

Right hand video tutorial done by Mikey from The Crochet Crowd

Left hand video tutorial done by Mikey from The Crochet Crowd