Basically, you make a file named "webtv list.m3u" with the following structure:
#EXTM3U
#EXTINF:-1, The Channel Name
http://(channel location data)
Continue to add channels in the same manner (lines 2 and 3, Line 1 is only at the beginning of the file).
Notepad works well, just be sure to make sure it is saved as .m3u and not .txt
Transfer the file to a USB drive, then in Web TV (under Applications), use "Load WebTV List.m3u" and the channels will load and appear in the list.
A few notes:
If you want to add or delete channels from your list, it is better to edit your file and re-load it.
When at the screen where you load the list, if you click on a channel, it will preview on the left, then click (OK button) again for full screen (have to click three times to get full screen, one click does give full screen, except the picture is still the size of the preview). Up and down buttons after this change channels and all are in full screen.
One anomaly I have found is that, for some reason, https:// locations, while it will load in the preview screen and then you can go to full screen, will not load once in full screen if using the up and down buttons to change channels to one that has https://. Most times, dropping out the "s" in https the channel still works, but the odd time you will find it won't work without the "s" and, therefore, you have to back out of full screen back to the preview screen to get it to load before going to full screen mode.
That's a start for now!