please help!!!!

[jaymoz]

i'm newish to knitting and have jumped in with both feet making my daughter a poncho style jumper, all was going well until it came to the sleeves!! its in a 3x3 rib pattern which i can handle..... then it decides to spring this little surprise on me... next row, rib 1, pick up loop between last and next stitch and work into the back of this loop (this will now be referred to as m1), rib to last st, m1, rib 1. 39 [43,45,47,51;51]sts. inc i st as before at each end of every 6th row to 45[51.55.51.59;59]sts, working inc sts in rib... i get the mi (after watching a video on here of how to do it ) but what i dont get is how to work the inc st into the rib pattern?? its all going completely wrong when i then carry on with the rib i was doing before the rib pattern is going skewiff and i am having to keep unpicking it all and starting again all advice would be gladly appriciated