The next part has several different possible names. Some people call it the "return" or the "return pass." Some people call it the "reverse;" this is the name given to it in The Harmony Guide to Crochet Stitches compiled by James Walters and Sylvia Cosh.
When following other designers' patterns constructed using this stitch, you'll find that some people call this "row 2" of the work, while others envision it as being the second half of row 1.
To complete the return pass / reverse for the Tunisian knit stitch, work a chain stitch by looping the yarn over your hook and pulling it through the last loop on your hook (Views I, J and K.)
*Yarn over (View L) and pull it through through two loops (Views M and N.)
Repeat from * all the way across the row until only one loop remains on your hook. (Views O and P) The remaining loop on the hook will count as the first stitch in the next row.
Again, the terminology for this aspect of the technique is not standardized. Some people call this "working off the loops;" you might read instructions telling you to "work off the loops by twos." Others refer to this as "binding off" or "casting off," which is perhaps how a knitter might express it; there are definite similarities here to the process of binding off in knitting. There are probably more ways than these to refer to this process; those terms are just a few that immediately come to mind.