There are 3 set up rows. Do you understand all 3 of them? Because if you do you know everything you need to know to do what they are saying on row 1. But I’ll explain it a bit in a second.
A M1L is also called a M1F and the M1R is called a M1B, I find those names more helpful. I don’t know what problem you are having, but maybe the stitch count isn’t coming out right or something like that. It could be that you don’t understand how to do the 2 increases correctly and that could effect the stitch count. There is a video about how to do these 2 increases in the video section and a short explanation in the “Glossary”. These increases are happening in the little strand running between the last stitch on the right needle and the next stitch on the left needle.
Row 1 (RS): K2, M1L, knit to center stitch, M1R, K1, M1L, knit to last 2 sts, M1R, K2
**Row 2 (WS): K2, purl to last 2 sts, K2
You have 7 stitches after you finish the 3 set up rows. The middle one is set apart by a marker on each side of it. You are going to be working in stockinette (knit a row, purl a row) with 2 sts of garter stitch (knit every row) on each side edge from this point.
Row 1: K2, then work a M1L, now knit to the first marker, do the M1R, slip the marker, k1, slip the second marker, do a M1L, knit until 2 stitches remain on the left needle and work a M1R, knit the last 2 stitches.
You want to keep only 1 stitch between the 2 markers all the time and slipping them the way I said will do that.
Row 2: always amounts to knitting the 2 stitches on each end and purling all the ones in the middle, slipping the markers as you come to them.
Then you just keep repeating rows 1 and 2. The number of stitches will keep growing to produce a triangle and it will be stockinette with 2 stitches of garter on each side.
When you have repeated 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, (which is 11 rows) you will be on a wrong side row (row 12), knit this row all the way across. This will throw a purl row to the front and make a decorative raised row.
Keep repeating rows 1-12 for as long as they say to.