From the bottom or from the top?

Hi everyone!

I’m knitting a “cozy feel-good cardigan,” and I need some help with it. Do I start at the cuff and knit upward with increases, or do I start at the top with decreases? It has a straight armhole, so I just need a guide based on the sleeve length—when, how much, and where to decrease or increase.
So it’s better to start at the top—that way, the circumference is set. But at what intervals do I knit down, and when do I make decreases? I hope I haven’t made this sound too complicated. And of course, I’m hoping for some help... Love, Patricia #Häkelomi 

Welcome to our group, Häkelomi.
I’m bumping this post again—maybe someone else would like to add something.