It is a big learning process, yes.
There are many of posts made by community members about the rules; and the biggest one is no plagiarism. Second would be no spamming.

Steemit is meant to be original content.

It is more than fine to link to someone else's video or content, but the person must put their own thoughts about it.

Here is a good video to watch for a start:

https://steemit.com/minnowsupportproject/@minnowsupport/community-posting-guidelines

I want to help you get noticed. I like what you write. I had wanted to vote, but then doubted whether you were the original author when I saw the Cheetah comment. Cheetah isn't saying that it is plagiarism, but is just one way for people to be more careful. Nobody wants to vote on plagiarized stuff, especially those people who have lots of voting power and could give you the most rewards.

You should probably add your Youtube channel in your profile as well, along with a description of what you are all about. Also mention on your youtube channel and website that you are on Steemit too. That way it's easier to know you are who you claim.

Anyways, you are allowed to post your own already-published articles over here on Steemit.
But it would be best to add a note to the top of bottom about how this is your original content, that has already been posted elsewhere on the web. Just make it quick and easy for people to tell so that they don't have to guess.