Hi My name is Trevor!

Now ive looked at 100s of Youtube videos that supposedly explain how youtubes SEO works and how to optomise it but they all do the same thing and go into supper technical talk that i swear is for rocket scientists. lol anyway if anyone could explain it to me as though i was five that would be awesome! lol the things i really want to know the most is
1 how it all works and what it looks for?
2 how can i tell if a tag is a good one or not?
3 where can i find good tags? (i have tube buddy and thats what i use now)
4 how do i go about promoting my videos or should i not promote them?
5 how do back links work?
6 how can i rank my videos better?
7 anything else that has to do with the SEO or making my channel better!
thank you so much for your time really it means alot that you stopped by and took a look at this thread and it would mean the world to me if you could answer these questions thank you so much!

i hope you all have an awesome day!
1) The basic concept: Youtube CANNOT see your video. So, "metadata" is a fancy way of describing your video to someone who has never seen your video, so that they can decide who to share that video with. If you were describing that video, you might use several tools: for example, you might just explain in sentences and paragraphs what the video is about ("description"). You might give a quick phrase to describe it ("title"). You might give them several general topics and words that the video is about ("tags"). And if you speak in the video, you might even give them a transcript so they would know what was said ("submitted subtitles.")
Additionally, YouTube does their own research by seeing what people who has already watched the videos already think about it. So they will ask people who watched the video, "Hey, how much of this video did you watch? How many other videos did you watch after ward." This is called "watch time" and is tracked in your "Analytics"
YouTube takes these two things -- "Metadata" and "analytics" -- to determine what topics and search terms are relevant to your videos, and how highly it should rank your videos. YouTube's goal is to maximize watch time for its viewers, so it wants to show its viewers videos that they are likely to enjoy so they will keep watching YouTube. Your job is to help YouTube understand where your videos would be most appreciated.
2) A tag is good if (1) it describes your content, (2) it is something that people would search for, and (3) is something that people would search for and want to see your content for. A tag is even better if you can rank in the first page of youtube search results for them.
3) You can do this in TubeBuddy, but one thing I usually do is I begin typing my proposed keywords in youtube search. Youtube will show auto-complete suggestions -- these represent search terms other people have actually searched for in the past, so I know that people are searching for those. If any of those are relevant to my video, I add them. (In TubeBuddy's Tag Explorer, this is the "Auto-Suggested" tab)
4) I think you want to make sure that your metadata (titles, tags, descriptions) is in a good place first...you want to make sure that you're getting a good amount of your traffic from YouTube search. That being said, if you want to promote, then you need to find communities that are targeted to your niche, and that you are already an active participant in. People can smell spam from a mile away, and they don't appreciate it, so you have to realize that promotion is about building relationships, providing people with what they want, etc.,
5) Backlinks don't really affect YouTube internal SEO, but the way they work in generally is that Google (for Google search purposes) looks at more factors than just the ones I mentioned in my answer to item (1) above. One of these is seeing that a particular article or site is getting engaged by other sites -- especially if those other sites already have credibility. So, getting backlinks is the process of getting your content linked from sites that Google has already identified as credible.
6) See answers to 1, 2, and 3. Ultimately, having good analytic data (watch time, audience retention) will matter in the long run (this is why you will find that there are often a lot of folks with really bad metadata in the first page of results -- they've already proven themselves with the watch time), but while you're small, you can do the best you can by targeting certain keywords effectively. You probably won't be able to rank for short keywords (e.g., one or two words), so you want to think of phrases that people might be searching for.
7) Submitted subtitles also contribute to SEO, so if you have a transcript to your videos, you might think about submitting them to youtube. Also, keep in mind that there are other factors which aren't purely "SEO" that can affect things. For example, it doesn't matter if you rank in page 1 of search if your thumbnails are unappealing, because people won't click if the thumbnail is really bad. And it doesn't matter if you have the best metadata in the world if the video is not engaging -- people will click away, and then your watch time and audience retention will be poor. Remember that YouTube ultimately cares about analytics -- what keeps viewers watching longer? So if your analytics are bad, then your videos will rank lower.