I got the pattern from http://www.yarnspirations.com called Bernat easy crochet hat.
I was never good at the seam but after redoing it and redoing it over and over about ten times I finally figured out something that worked for me.
At the end of each row before finishing the last stitch. Leaving two strands on and add other color finishing off that stitch. And instead of joining or changing one any of that. I just single crocheted new color in the next stitch. The row below should be the new color. Did that each row and didn’t make any seam in the hat or any colors out of order.
Hopefully that helps and you can understand that. Know most crocheters should least not beginners should understand but always here for any questions and I’ll answer them the best that I can. 😘