Material and tool:
Main Color yarn: 100 g Worsted weight yarn.
Contrasting Color yarn: 50 g DK weigth yarn;
Crochet hook size 3,5 mm(E); hook size 3 mm(D);
Stitches and Abbreviations: (US terminology)
Chain - ch
Single crochet - -sc
Slip stitch – ss
Treble crochet – tr
Back post single crochet -bpsc
Slip stitch - sl st

You can use multiple strands of the yarns for Main Color to make up a single strand of Worsted weight.
You can use multiple strands of the yarns for Contrasting Color to make up a single strand of DK weight.