Okay so I am pretty new to knitting. I’ve learned to knit and to purl and I’m getting to adding new yarn and stripes or whatever-
But for Christmas I am knitting 3 scarves. One is going to be plain color. One is going to be simply striped but the BEST one-
I want to look something like this!

I have the yarn, but the design is kinda complicated for a beginner and I’ve never used a pattern or made my own pattern!
My grandmother is an experienced knitter, but she just got out of the hospital! I’m hoping maybe the people of the internet could help a knittingnoob like me? ;uu;
Thanks anyway for reading this even if you can’t help!
(Also I apologize if I have been disrespectful or ignorant in anyway. Like I said, I’m very new to knitting. I’ve only been knitting for a few months!)
H and welcome to KH! You’ve asked a great question expecially since thate are several ways to answer it.
The stripes are easy enough to do just by changing yarn color. If you knit the scarf flat, that is back and forth as you’ve probably done before, you’ll need to work in a non-curling stitch like garter stitch (all knit rows). You could also do stockintte stitch (alternating rows of all knit across and all purl across) but you’ll need to add on a garter stitch border to keep the scarf from curling.
The diamond design can be worked flat in either garter or stockinette pattern but it will look great on one side and not so perfect on the other side. You can find a knitting chart for the diamond online or draw your own on graph paper.
Knitting a tube hides the wrong side but it has it’s problems with designs like the diamond although there are work arounds for that too.
If it was me I think I’d opt to work using a flat border stitch like garter or seed stitch on each side for about an inch so it would lie flat. The middle I would do stockinette (knit a row, purl a row). As you work your stripes keep track of how many rows you put of each color so you can do the same thing on both ends. I’d suggest intarsia for the diamond. You can draw a chart yourself and it would be best on some knitters graph paper (do a Google search and you’ll find sources where you can print some up yourself), but regular will work or just draw some up yourself. Check out how to do intarsia in the free videos section. Look under "Advanced Techniques (don’t panic), scroll down to “How to knit with 2 colors at a time” and then pick “Intarsia”. You could also use a technique called duplicate stitch. For that you just knit the space where the diamond will go (think ahead so you can center it both ways) then using your ‘purple’ yarn embroider the diamond on over each knit stitch so that it ends up looking like it was knit right on. If done neatly either of those will not look bad on the back side but not like the front by any means.
It is neat that you are starting early on to design things yourself, you learn so much that way and become more independent sooner. And BTW I wish I had your computer skills to create that picture and caption for us.