In case videos are not so easy for you (as they aren’t for me)… When you have knitted a stitch, so have at least 1 stitch on the right hand needle (RHN), it will be the little strand of yarn that runs between the last stitch on the RHN and the first one on the left hand needle (LHN).
For the M1B go behind that strand with the LHN and pick it up so that you now have a loop on the LHN. Now knit into the front of that loop just as though it were a knit stitch (only it is a little different and will close the stitch instead of opening it up like a normal knit, twisting it)
For the M1F do the same, but pick the strand up to form a loop from the front of the work, then knit it like you would for any through back loop instruction. It seems complicated, but remember if you pick it up in front you work it in back and vise versa. Twisting closes the holes you’d have otherwise.