Question about patterns

Hi, I am very new to knitting and would appreciate some insight! I wanted to try a more complicated stitch pattern, but I’m a little confused. I’m not sure home many stitches i should cast on, and I’m not sure what the pattern means when it says that it is worked in a multiple of 8 stitches plus 1…when Row 3 calls for me to "knit 4, *purl 1, knit 7; repeat from * to last 5 stitches, purl 1, knit 4."
Here is the pattern (Diamonds in Columns):
Row 1 (right side): Knit
Row 2 (wrong side): Knit 1, *purl 7, knit 1; repeat from * to end.
Row 3: Knit 4, *purl 1, knit 7; repeat from * to last 5 stitches, purl 1, knit 4.
Row 4: Knit 1, *purl 2, knit 1, purl 1, knit 1, purl 2, knit 1; repeat from * to end.
Row 5: Knit 2, * [purl 1, knit 1] twice, purl 1, knit 3; repeat from * to last 7 stitches, [purl 1, knit 1] twice, purl 1, knit 2.
Row 6: Repeat row 4
Row 7: Repeat row 3
Row 8: Repeat row 2

I would really appreciate any help that anyone can give!!

Most patterns are made by repeating the same sequence of stitches over & over.
The diamond is made using 8 stitch for each diamond, plus 1 for an edge. So that is described as “multiple of 8 stitches plus 1.” So you could work a full set of diamonds on any of these number of stitches, ie 9,17,25,33,41,49 etc.

So count your stitches on the needle. Subtract 1, then divide by 8. You should get a whole number which will equal the number of repeats.

To read the pattern, anything between the * to *, get worked over & over in that row.
For example-
Row 3: Knit 4, *purl 1, knit 7; repeat from * to last 5 stitches, purl 1, knit 4.

You knit 4
Then repeat this sequence-purl 1, knit 7 over & over
Til you get to where 5 stitches remain on the left needle, then you purl 1, knit 4.

Thank you Abby! That makes sense to me now! I just figured it out today.
I had to figure it out in a different way though, for it to register with me. To answer the question I had…“how many stitches do I cast on??” You can cast on any number of stitches that can be divided by 8, then add 1. (As Abby said, 9, 17, 25, 33, 41 - that is 8, plus 1; 16, plus 1; 24, plus 1; and so on.) I decided to try casting on 25 stitches (24 plus 1.) Now this is how I figured it out…if this is confusing to anyone else then I’m sorry! But I thought I would add my two cents. Hope it helps!
Here goes: If you decide to cast on 25 stitches…

For Row 3 - Take the total # of stitches (ex. 25). Now from 25, subtract the required # of stitches you are asked to knit first (in this case, 4). This gives you 21. Next subtract the # of stitches you are asked to stitch last (in this case, 5). You are now left with 16 stitches. This is where the multiple of 8 comes in. These are the stitches that you are asked to stitch from the * to the ; over and over again. For row 3 you would repeat it twice.
So row 3 would look like this, if I decided to cast on 25 stitches:
Knit 4, (purl 1, knit 7), (purl 1, knit 7), then the last 5 stitches (purl 1, knit 4). If you add all the stitches together, they add up to 25.

If you decided to cast on 33 stitches in the beginning, your row 3 would only change when it comes to the repeat…the stitches between the * and the ;. Instead of repeating the (purl 1, knit 7) stitches twice, you would repeat it three times. If you decided to cast on 41 stitches, you would repeat the (purl 1, knit 7) four times…and so on.

Like I said, this helped me!