Turning chains in a crochet chart: how each row starts
Every row opens with a turning chain chosen by its stitch. Chain One draws it for you.
On the Rectangular canvas, a row opens with a starting chain, also called a turning chain. The stitch the row is worked in decides how long it is.
Single crochet (sc) uses chain 1, which is not counted as a stitch. Half double crochet (hdc) uses chain 2. Double crochet (dc) uses chain 3. Treble crochet (tr) uses chain 4. Double treble crochet (dtr) uses chain 5. For these taller stitches the chain counts as the first stitch of the row.
Increases, decreases and front or back post stitches take the chain of their basic stitch.
Chain One records the starting chain as part of the row itself. Painting stitches across a row never paints over it. It appears where your stroke reaches it: first if you paint from its side, last if you paint toward it.