Work a number of rows for the tuck with a contrasting color starting from WS.
Number of rows depends on how thick the yarn is, and how big of a tuck you want. Finish with a row from RS. The video is showing you 2 ways of doing the tuck:
1st with a ridge: using main color * pull up the top of st from the last row knitted with main color, put loop on right needle, P 1, pass the pulled-up loop over the P st *, repeat * - *
2nd without ridge: using main color * pull up the top of st from the first row knitted with tuck color, put loop on left needle, P the loop and following st together *, repeat * - *