When you start on a crochet project, check whether the pattern you are following is American or British as stitch names differ between the two countries.
GB Single crochet (sc) = USA Slip stich (sl st)
GB Double crochet (dc) = USA Single crochet (sc)
GB Half treble (htr) = USA Half double (hdc)
GB Treble (tr) = USA Double crochet (dc)
GB Double treble (dtr) = USA Triple crochet (tr)
GB Treble treble (trtr) = USA Double triple (dtr)