Need clarification on pattern

I found a cute boys jacket pattern at (#70623AD) that I want to knit, but I’ve never used a pattern before and I don’t understand what they’re saying. The entire jacket uses garter stitch, and this is where I get lost. You start with the back of the jacket, cast on 48 stiches. Then it says “work even in Garter st (k every row) until back measures 14 in from beg.” I don’t understand what it means when it says “[I]work even [/I]in garter stitch”.

I also want to change the pattern to make a ribbing along the bottom of the jacket and the bottom of the sleeves. Most patterns I’ve seen step down a needle size for ribbing. Should I do this?

Last question, this is going to be a college football team jacket for my 1-year-old grandson. Will garter look nice, or should I do stockinette?

Thanks for any help you can give me–I’m really stepping outside my comfort zone by anything that’s not a blanket. And I’m ready to start knitting it today while watching football.

Work even in a pattern means to do no incs or decs. It usually follows a row or section with incs or decs, but sometimes it’s used the way it is in this pattern.

Ribbing is usually done with a smaller size needle because the sts are a bit looser than stockinette and it looks off when you use the same size as the stockinette, so you can use a smaller needle if you wish.

So you think the stockinette would be nicer for a little boy than all garter? I was thinking about garter as called for in the pattern with the ribbing, but I don’t know if that can be done and look cute.

I just need a simple sweater pattern that’s predominately red with a few white accent stripes. If this one isn’t good, can you suggest something?

I overlooked the garter stitch part. Ribbing is usually done with stockinette to keep it from curling which you don’t need with the garter stitch. It’s unusual to match ribbing with garter, but not unheard of and if you’d like to try it that way, go ahead, it’s your sweater.