Attempting a lace shawl and can’t get past the directions: When there is a double yarn over indicated by (yo)2x, the next row uses this double yo to make 2 sts. The first st is knit regular, the second st is knit into the the back.
Welcome to Knitting Help!
It means literally to put the right needle down into the back loop of the stitch. The easiest for you to understand it is look at the video. Check the Glossary tab above and look for “k tbl”.