I already have a post about the basics of posting on a world...but here is a post on making a world so you can post! (well the article is more specifically stories, but you can use it for posting other things too)
Well, the Worlds are nice because you can make a few to organize your things (like opinions, stories, videos, clubs, etc) however you'd like to. I believe that regular members (vs. premium accounts) can have up to 5. Then there's also guest posting too, but we'll cover that later ^^
So after you decided how you want your world(s) to be, go to your back room and on the navigation bar, move your mouse over "Worlds" and select "Create World"
Line 1: World Title
What you want the world to be called, for example I have this world called "Big Sister" and that's how it shows up on my portfolio
Line 2: World URL
A URL is the web address, TheO already provides a good portion of it, you just need to put the rest of it *note, avoid spaces and periods etc.* in the box I just added "bigsis" so the address for this page you will note is the TheO address/bigsis
Line 3: One Line Description
This will be something to explain whats on the world for people looking up worlds to see, like for this world I would say, "A World where people can get help from a sister, covering all sorts of problems as presented."
Line 4: Category (optional)
Do you have a site dedicated to a particular anime, it's good to mention that here if you want people of similar interest to find your world 
Line 5: Tags (optional)
Another good thing to put themes in like 'fanfic' or a specific character or characters that will be in the post on the site ^^ Just another tool for people to find you!
Line 6: Open to
Everyone, Members Only, Friends Only, Just Me
That's pretty self-explanatory, you choose who can read your posts!
(woah, you mean I could have a personal journal on-line that's only for me?!)
click Create World under that and TA DA! Congrats you have a world!
You can begin posting now, but here are some other World options you have:
{note, first you'll be asked which world before going on to the page with the selected option}
"Modify World"
If you want to change anything you did in the previous step. The layout is the same as the create world page, but there is also a DELETE FOREVER DANGER box you can click and hit Edit World. If you do that, I suggest you move any posts on it that you want to save to another world first!
"Introductions"
Write down what you want on the top of your world before your post begin
A good idea is to explain what your world will be about ^^
You may have up to 1 video and 1 image in your introduction using the codes they give you with the : in the box you're typing the intro in and loading them below the box you type the message in.
Click "Edit Introduction" when you're done.
"Edit Guest Posters"
That's right, you can allow other people to post on your worlds! Go to the world you want and add the member's username, one name per line.
Hit the update button underneath and then those people will be allowed to guest post on that world of yours!
"Edit Designs"
Now this is the fun one! Here you get to make your site pretty with themes, upload bgs, change the font and colors.
For this one I'd say have fun with it. Explore and experiment. It takes some time going from the design page and seeing how it looks on the World, but it's the best way to personalize the world to be yours! :3
I think that should cover everything, feel free to ask any further questions regarding making worlds so you can post! HAVE FUN!
