A multiple is how many sts are in just the stitch pattern, so you would multiply the 26 times how many repeats and add 3 more. So it could be 55 (26x2+3) sts or 81 (26x3+3), or 107, etc for the pattern. The 9 sts at the beg and end are edge sts that aren't repeated.
This is just for a stitch pattern only, if you just wanted a scarf you would do one repeat of 26+3 plus 4 or 6 more for edge sts. For something wider, see above.
sue- knitting heretic