I have one!
I remember talking about it a while ago but I erased the link from my post just in case anyone I knew in real life found it xD I might end up doing that again after I post it on here. Well mine is http://godricsxhollow.tumblr.com/
Mine is mostly Harry Potter related with occasional random stuff on it. I follow a bunch of Harry Potter Tumblrs so whatever they blog, I reblog it.
WARNING: DO. NOT. GET. ADDICTED.
I was SO addicted that I used to put off my homework just to go on Tumblr. TIME YOURSELF. DO NOT get carried away on it. Now, I barely use it. I just don't really have time to go online anymore but omgsh, there are SO many funny things that go around that you'll find yourself cracking up and your family will think you're weird. XD Remember how I would put some photos up here about Darren or the StarKids or something like that? Yup, well they were from Tumblr!
Anyways! Well what exactly would you like help on?
Like the basics? It's really easy to use once you get used to it.
Well first, you should follow a bunch of people. That way, they'll look at your blog and some might follow you back and reblog some of the stuff you post.
As for customization, well where it says "customize", it takes you to your blog. Well click on "Info" and that's where you type your blog's title and your 'about me' in the description. The theme is how your background looks. I would click on the bottom of it, where it says 'browse more themes'. There's A LOT to choose from, it just takes a while to load. Then there's the "Appearance" tab, I wouldn't mess with it because the "Theme" already takes care of that. I would leave "Pages" blank as well as "Services". For "Community", I would check the boxes that says allow replies from people you follow and let people ask questions. That way, your followers can talk to you and trust me, if you spend a lot of time on Tumblr, you get really close with some of your followers. It's like another family, kinda like with AW. And also, don't mess with "Advanced".
Okay! Now what else.. Hmm.. okay well basically just reblog a bunch of stuff, this will get your Tumblr name more known so people will be more likely to follow you. And you can 'like' a bunch of stuff by clicking on the heart. This shows up in your 'liked *insert number* posts' but this is just for you when it's one of those things that you don't want to put on your blog but you like it so you just like it to look at later. Or if one of your followers rants/says stuff, you can like it to show you care.
Well that's all I can think of right now but if you need anything else, I'll be sure to help!