OK, you have yarn and needles, and you have YouTube. Most importantly you are a crocheter, so you’ve got this! You know your way around a pattern and you know how to wrangle yarn.
What you need are two things: comfort with The Knit Stitch, and a recipe for making a blanket.
I grew up knitting English style (“throwing”) and decided phooey on that at some point, and locked myself in my craft room for three days with YouTube, and emerged knitting Continental like a pro! YouTube is awesome for learning to knit, you can play the demo back a million times, even in slo-mo, until the light bulbs are going on in your brain and your hands.
So while it is true that the Blanket Stitch is actually a sewn edging stitch, not a knitting technique, yes you can totally accomplish that. I just reviewed some of the top YouTube hits on how it is done, and they are very clear. But first you need a blanket to perform the Blanket Stitch upon!
My advice would be to focus on one thing, the knitting stitch. You can make an entire blanket with just that stitch: knitting back and forth, using the knit stitch for every row both front and back. This is called “Garter Stitch”. The beauty part of Garter Stitch is it will not roll. It makes a very cozy fabric that lays nice and flat. It would look glorious with a contrasting Blanket Stitch edge!
Here is a lovely tutorial offered at “All About Ami”, in which Stephanie walks you through casting on and working Garter Stitch. Her finished project is a gorgeous oversized Garter Stitch scarf, so you can see how pretty it knits up. Also for your consideration, here is her free “Simple Garter Stitch Blanket” pattern!
Another potential resource to get you off on the right foot is this tutorial by Vickie Howell, in which she offers step-by-step instructions on how to knit a blanket from a “recipe”. In other words, you don’t really need a pattern, it is just a square or rectangle, so there is no issue of it being a certain size or proportion in order to fit properly. She walks you through how to create a “Gauge Swatch”, which gives you data on stitch and row counts. These numbers help you cast on the right amount of stitches for the width of your blanket. Then you knit it until it is the length you want, and Voila!
There is some math involved, but Vickie Howell makes it very easy with a convenient “Blanket Recipe Worksheet”, which she walks you through. I would recommend just keeping things super simple with straight Garter Stitch and no borders, then Blanket Stitch the edges...
(It would be awesome to see a photo of your finished project!)