Throw Pattern conversion question

I am new to knitting I found a pattern for a throw that I want to knit but I don’t want to use the yarn that they have suggested. They suggest that I use a bulky yarn but I have already purchased some simply soft yarn that is labeled as being a 4. Is it possible to substitute the yarn (I assume that it is) and if so what kind of adjustments do I need to make? If anyone has any suggestions please let me know. Also, if there is a similar pattern out there that I won’t have to change please let me know. Thanks so much.

Here is the link to the pattern:

You can double the yarn, and that would probably work.

Or you can cast on more sts for each strip and knit more rows in each color. In the original yarn, the strips are about 12" wide and you have 5 of them making it 60" wide. If you don’t want one that large, you would see how many sts/inch you get and multiply that by how many inches you want each strip to be. It’s a simple garter stitch, so you don’t have to adjust for a stitch pattern. I might add, you may want to just double the yarn to make it go faster; that much garter stitch drives knitters to poke their eyes out with their needles!