Welcome to the forums, I am sure you'll get into some interesting discussions.
Have any advice for me as a newbie?
I have some.
The first would be to read the rules. They're not all your typical forums rules as we have rules for discussion. Generally it is considered important and fair that people stick to them.
Anything you say you will be held accountable for, so if you do break a rule, like say, if you shift a goal post, people will likely pick you up on it and they'll be able to easily find your original statements. Not saying that you will do this, but it's quite common, so I thought it worth mentioning.
Preaching. This is a big 'no'. I just watch the video you posted and I can understand where he's coming from, from the eyes of a Christian what you're doing is saving us, because you don't want us to suffer. I can appreciate that, conversely as an atheist who doesn't believe in the bible, I see that you're living a delusion and are wasting your life, you only have one life and it shouldn't be living in fear of going to hell or worshipping a non-existent God or even restricting yourself because of your faith. To me, breaking you free of that would be a kind act. However, there's a few things I understand, one of them is that if I were to 'preach' my atheism to you or to come from the angle that I'm 'saving' you, then there's a high chance you'll be turned off and it won't work. I accept that you don't think or feel the same way I do about it. I understand there's the prospect of being wrong, no matter how much I think I am right, I am human therefore I am susceptible to error, so I remain open minded and don't assume with great authority that I'm right, this means if somebody were to show me that I'm wrong, then I will change my mind. If I am right and you can be convinced, then I feel the best way is through science and reason. I can't just sit there and tell you there is no God, just as you can't sit there and tell me that there is one or sit there and tell me that bible is true and use the bible to back all those claims up.
So I think, coming back to the point here, you won't reach out to anybody if you've come here to preach or even come here with the attitude that you're coming to 'save' us. Because that says to us, "you're not willing to listen, you're not willing to accept the prospect that you might be wrong and that any discussion will be one-sided" and that's not how it works and of course, it's not really fair on anybody.
Intellectual honesty will go a long way. Even if people don't like what you're saying, don't ever try to deceive anybody or try to be intellectually dishonest, this ties with our rules of discussion, for example, shifting goal posts, stonewalling, making strawmen, dodging and refusing to provide back up to any claims where asked. If you don't know the answer to a question or you feel you can't provide what people are expecting. Be sure to state it, if you can't argue a point, it doesn't mean you've lost, it just means your argument isn't strong enough or you don't have the research for it. If it gets to that, be sure that you won't be able to convince people that your argument is valid and the reason they're not agreeing with you is not that they're blind to the truth (as people have claimed before) it's just you've not got enough to back your own claims to convince them otherwise. Yes, we're a tough bunch to crack and to be fair, so are you guys.
If you're ever overwhelmed, as there's a lot of people on this forum and many will offer lengthy replies, then say so, do your best to address everybody, but also understand we prefer quality over quantity, so lets say you only have 30 minutes to reply, it'd be better for you say, "I'm sorry I can't address all of your posts and I will try and get back to them, but there's so many" and then say, spend those 30 minutes on a well thought-out reply to one post, rather than short responses to many posts. Of course, if you're commonly overwhelmed, we do have 'The Shelter', which is much more relaxed.
I think the important thing to note is that this place, for theists and atheists alike, require people with thick skin who won't cave in under pressure. The reason I say this is that discussions can get pretty heated and in depth and people do try and scrutinise and sometimes even to a fine detail. This is the kind of discussion forum this is and it isn't for everybody. My advice would be, don't take anything personally, but if somebody does step out of line, report them, unfortunately, mods aren't omniscient and don't see everything that goes on.
There's a lot to bear in mind there, I know, but don't let it scare you and I hope it helps you. We're actually nice people, I hope that you do stick around and get into some interesting discussion and debate. People tend to get banned from here because they don't respect our rules and how this forum operates and you wouldn't believe how many people have failed to do so, but we do get people like magicmiles who do their best and are respected for it.
Also, we've got a 'chatter' section, feel free to join in for something more casual or even for some banter.