How is tbl and how do you do it?
tbl meens ‘through the back loop’.
On your needle each stitch will have a ‘leg’ or ‘loop’ which is nearer to you or to the front and a leg that is further away or too the back. Normally when you knit a stitch you go through the front leg but when doing a Ktbl you would insert your needle in the back leg instead.
knitting through tthe back loop can be a method on it’s own to purposfully twist a stitch or can be used in conjunction with a normal knit as an increase (known as ‘knit front and back’ or Kfb).
There is an explanation of Ktbl in the glossary and a video of KFB in the increases section of the videos.