Hearth & Harbor Crochet Counter, Crochet Hook Set with Crochet

I got this row-counter in my beginner crochet kit. It does not explain how to use it. How does this thing work? I can manually switch the numbers, but what is the

Super Easy DIY Row Counter for Knitting and Crochet - The Artisan Life

Amethyst - Knitting Row Counter - Twice Sheared Sheep

How to Count Single Crochet Rows

Hearth & Harbor Crochet Set Kit with Yarn and Crochet Hook Set (96pc), Size: Crochet Set + Crochet Counter

Hearth & Harbor Mini Crochet Set Kit with Yarn and Crochet Hook Set (68pc), Size: Mini Crochet Set + Crochet Counter

HCBZVV Counting Crochet Hook Set with Case,12 Size Uganda

Crochet Counting Hook & Handle Set - 12 Hooks 2mm-8mm

Counting Crochet Hook Set Digital,Ergonomic Crochet

Crochet Counting Hook & Handle Set - 17 Light Up Hooks - Comfortable Ergonomic Soft Grip - w/Digital LED Row Stitch Finger Counter Marker Easy to Read Numbers - Crocheting Knitting