Stars, brackets, "rep from", a number at the end. Paste one row or round from any crochet pattern and see it in plain words, drawn out in stitch symbols, with the stitch count checked for you.
It reads the line with the rules patterns are written by. It does not guess: if it cannot read a part, it says so. Left-handed? The words are the same for you. You work each row in the opposite direction.
Everything between the two stars is one block. Work the block once, then go back to the first star and work it again, as many times as the pattern says. So this one is: sc 2, ch 1, sc 2, ch 1, sc 2, ch 1. If it says "repeat from * to end", keep working the block until you run out of stitches.
Round and square brackets do the same job as stars: work what is inside, then do it again the number of times shown after the bracket. When a bracket is followed by "in next st", it means something different: everything inside goes into that one stitch.
That is how many stitches you should have when the row is done. Count yours every row while a pattern is new to you. If the numbers differ, you have found the mistake while it is one row deep.
"2 sc" on its own usually means one single crochet in each of the next 2 stitches. "2 sc in next st" means both go into the same stitch. That is an increase, and it is the most common place to go wrong.
The Crochets designer writes every row of your own pattern with the stitch count at the end, draws the diagram in standard symbols, and works out the yarn. It has a left-handed mode. Try it free.
Related: US and UK terms converter · Foundation chain calculator · Yarn calculator