Be sure to check posting dates. The thread you posted to is very old and unrelated to your quest. So this new one was started for you.
A good place to begin with Videopad is to view the tutorials. https://nch.invisionzone.com/topic/23872-videopad-tutorials
DOWNloading, from YouTube, TikTok, etc. has nothing to do with Videopad. You get what you get. But UPloading to those sites from Videopad - even using the trial and free versions - does not place a logo (watermark) on exports.
For instructions on how to upload to TikTok... https://blog.hubspot.com/marketing/how-to-use-tiktok
If Videopad issues crop up, post a new thread with a descriptive subject and specifics on the problem. Someone will be glad to help.