This pattern has both the potholder and the placemat/trivet. There are written instructions as well as a chart. The potholder is made holding 2 strands of yarn at the same time. I do think the placemats could be made using only a single strand as you wouldn’t need the thickness to ward of heat.
This can be made using any colors you wish. It is made with cotton yarn to prevent melting.

MATERIALS NEEDED:
Worsted Weight 4 Yarn in I Love this Cotton in A (Arrowhead color) - Approx 200 yds
Worsted Weight 4 Yarn in B (Letters) - Approx 80 yds
Worsted Weight 4 Yarn in C (Edge) - Approx 10 yds
3.5mm hook (For the trivet/placemat, use a 5mm hook)
Scissors
Stitch Markers
Tapestry Needle

Stitches used and abbreviations:
Ch - chain stitch
MR - magic ring
St - stitch
Sc - single crochet
Sctog or dec - single crochet 2 together
2sc - 2 sc in the same st
Dec - single crochet 2 together
Sl st - slip stitch
Sc2 - single crochet in the next 2 stitches
Invisible join
FO - Fasten off