Hi. I am knitting mittens for the first time and there is something I don’ t understand in the pattern. The pattern says before starting first round to slip two sts from the second to the first needle. Ok I did that. My question is , when I make the first round those two sts will be at the end of the first neefle. Right; I move on to the second needle for the next 14sts without knitting the two slip sts?

You’re just rearranging the number of sts on the needles. All of the sts are worked.
Work the first needle sts as given in round 1. That’ll take 18sts to work plus 2 increases in sts for a total of 20sts on needle 1 after you do the instructions. Then go on to needle 2 etc…

Thanks for the help