Casting on

I am doing an Amigurumi
Pattern says for thumb:

Cast on 5 Sts at beginning of next 2 rows .

I am working on Flat.
Does it means after my last row which is the RS. will I make backwardf Cast on, then purl it on the WS… Then when I turn on the next Row ( RS ) I will cast on again 5 Sts.

Pls can anybody help me?
Thank you very much

Welcome!
Before you begin the next row, cast on 5 sts. Work those 5sts either knit or purl, whatever stitch should be done on that row. Work to the end of the row, turn your work and again cast on 5sts and knit or purl those sts and then the rest of the row.