Peekaboo mittens help

Hi, I am knitting these mittens which I printed from magknits.
What or how do I
Work to first gusset marker, transfer 9 gusset sts to stitch holder then remove markers, (don’t understand or how to knit this row)
use backward loop method to CO 4sts over the gap, k to end.

This is an opening for fingers out and fingers in modes.
Hope you can help.
Thank you:knitting:

Without more to go on…I’m guessing you’ve placed markers and have been increasing inside those markers to make the 9 gusset stitches. What is asking you to do is knit to the first stitch marker denoting the section of gusset stitches. Now, instead of slipping the marker and knitting the next 9 sts, take the marker off the needle and slip the 9 sts onto a stitch holder without knitting them. Close the st holder and take the stitch marker after the 9 sts off the left needle. Now, using the backward loop CO method (video of which is found here under Single Cast-on) cast 4 sts onto your right needle. Now, ignoring the sts on the st holder (and making sure the stitch holder is in FRONT of your needles), finish knitting the sts on your left needle. Make sure to make your first stitch or two after you cast-on you 4 sts a little tight so it doesn’t leave a hole where you join with the sts on your left needle. Hope this helps.

Thank you very much Liz. I seem to always not give enough information to my questions. Just lucky you know what I’m talking about and I mean lucky.
I will have to practice this but thank you so much.
Have a great week!