Knit 1 purl 1?

I am really new at this… I am supposed to do 4 rows of knit 1 purl 1 and it says "don’t forget to put your yarn behind for knit stitches and in front for purl stitches- everytime"
I for the life of me… can’t figure it out. I did one row and had about double the stitches when I started back for the second row and they just, I can’t even think of how to explain it… some were angled one direction and then they would switch to the other. With twice as many as I started with… can anyone help???
So far all I have accomplished is a couple scarves with just the knit stitch. I just learned to purl… I am really a beginner!

When you knit, the yarn has to come from behind your needle.

When you purl, the yarn has to come from in front of your needle.

When you switch between knit and purl, you have to bring the yarn between the needles to the back for knit and to the front for purl.

What you were doing were accidental yarnovers where the yarn was wrapping around the needle an extra time.

The best way I can think of to explain it is to think of the needles as like the two sides of a drawbridge, and the wool goes between them like a ship. That’s the movement. Try looking online for videos or pictures maybe?
Sarah