Another Mitten question

[MichelleLeigh]

Okay...
I'm still at the "decrease for thumb" section. Pattern says: K21, cast on 3sts, K rem 18sts.

My question is after I cast on 3sts do I knit those sts or skip them and knit the rem sts?

I went ahead and just knitted the 3 new sts, but it doesn't seem to make sense looking at it. Now it's just a little glob of sts right there. Looks odd.

Thanks for your time.
Michelle