Crochet chain
US and UK ch are the same stitch. Each yarn-over pulled through the working loop adds one chain.
Counted practice swatch
Make 16 chains, excluding the loop on the hook.
Work the repeat
Hold the slip knot, yarn over and pull through the loop. Repeat. For a 15-stitch single-crochet sample, work into the second chain from the hook and every chain after it.
Read the fabric
Look for 16 V shapes. Keep the back bumps loose enough to insert the hook; the working hook loop is never a counted chain.