If you’re starting from scratch, it’s best to work a couple of rows of standard stitches first, to give your fabric a sturdy foundation (I worked 10 trebles for four rows).
Step 1 Start a new row with a turning chain – for extended stitches, just work the same number of chains as you would for the standard stitch that you’re adapting. For extended trebles (ex tr) make a ch3 turning chain as usual for treble stitches. (For htr ch2, for dtr ch4.) As with standard stitches, the turning chain usually counts as the first stitch, except in double crochet.