How to increase / decrease stitches

Hi,
I am a beginner and I have a pretty basic question.
I am following a pattern that looks something like this:
(It makes a diamond shape)
[CENTER]

xx
xx
xxxx
xxxx
xxxxxx
xxxxxx
xxxxxxxx
xxxxxxxx
xxxxxx
xxxxxx
xxxx
xxxx
xx
xx[/CENTER]

I am totally lost with the concept of increasing/decreasing stitches.
from googling a bit, I can see that there are different methods such as M1, YO - but how do I know which to use? besides, I need to add the stich at the begining/end of the row and M1 is adding it in the middle of the row.
Please help!

If your row is only 2 or 3 sts, then an inc will be in the middle, doesn’t matter which one it is. A yo makes a hole and you may not want that. The inc can also be done one stitch in from the edge, doesn’t have to be in the very end stitch. So you can do kfb, knit… kfb knit the last st, or k1, m1, knit… m1, knit.

Thanks for your reply. for some reason I think I’m supposed to cast on in the middle of the work. I’ll try out different options and see what looks best.

If you only have a few sts on a row, like 2 or 3, then you would actually inc in the middle of it, because there’s no other stitches. But then the next inc row they can be more toward the sides. So if you have 2 sts, you would kfb, k1, or k1 m1 k1. then the next time you have 3 sts and can kfb, k1, kfb, or k1, m1, k1 m1 k1 and end up with 5 sts.

Take a look at the Free Videos tab at the top of the page, Increases. The demo piece running down the page shows the effects of various increases (see also Decreases) and gives you an idea of how to acheive the diamond shape.