Help please don't understand this part

Hi please can someone help with this knitting pattern
Cast on 261
1st row. K1, * k3, cast off 3 sts (1 st rem on right hand needle), cast off 5 sts (1st rem on right hand needle), cast off 3 sts (1 st rem on right hand needle), k3, rep from * to end. 118 sts.

Welcome to KH!
What is the name of your pattern?
The repeat is k3 then knit 2sts, lift the first over the 2nd and off the needle, knit one more, lift the first over the 2nd and off and repeat this by knitting one more and lifting the first over the 2nd and off. You’ll be left with 4sts, a gap where the 3sts were cast off and a single stitch on the right hand needle.
Continue with the given number of sts cast off until the end of the repeat. Then start again at the first asterisk and repeat until the end of the row.
Don’t count the stitch remaining on the needle after the cast off as part of the next cast off.