Failed to download m3u8, despite following instructions?

The web video has 2 m3u8 urls list.m3u8 and 720p.m3u8

 there was no master.m3u8 or index.m3u8here are the instructions:1-Open Chrome Developer tools and click the Network tab. 2-Navigate to the page with the video and get it to start playing. 3-Filter the list of files to "m3u8". 4-Find master.m3u8 or index.m3u8 and click on it. 5-Save the file to disk and look inside it. 6-If the file contains a single m3u8 master url, copy that one instead. 7-Run the program m3u8x. 8-Paste the same m3u8 url in both textboxes (URL and Quality URL) and click "Headers" and set the referral url and user-agent from the request as found in Chrome. 9-Select the Video format of "MP4". 10-Checkmark "One .. One". 11-Click "Download". 12-A dialog will display with all of the individual .ts files. Click "Download" to download them all and join them together.

This is the web video I am talking about:

 https://www8.123movies.st/watch/a-guy-thing.zlr13/...

I used youtubedlg_0.4 and m3u8x