Creating Your Character
At the very top left, you're going to see these links. Click "+ Submit", and from the dropdown, select "Character".
You'll be brought to a page like this. The avatar is what everyone will see before they view your character, so make sure you set a good one that's SFW and not obscene. This should be of your character's face, and should be square. Next, you'll set their name. Their name will be what everyone sees when they post, so make sure you use your character's proper name, ideally in Proper Capitals.
You can worry about sorting later on at your own time, though it's a good idea to use tags, such as #human or #furry, or whatever your character might be. The main text area is where you'll put all of your profile information, and while it doesn't need filled in at this step, it does need filled in before you can roleplay. You can use fields to help display information, and you can also find or code your own html bio templates, although that is also not necessary.
As a final note, you cannot upload canon characters to the site. A workaround I've found is not naming the folder after the canon character, should you have an offshoot character that's barely a canon. This won't apply to Arcadia however, as canon characters cannot be played. If you should upload a canon, then ToyHouse will lock your character so that no one else can view it except you.
Submitting an Image
Back at the top left, click "+ Submit", and then click "Image".
You'll see this page. Start with uploading your art file, which has to have been saved to your computer first. Crop it nicely to the face using the avatar tool. Your next step is adding a character, at the top right.
Click "Select" and find the character folder for your image. If there's more than one character, you can click "+ Add Character" and simply adjust the face icon from the new character folder.
Next comes artist credit. At default, it will have your name. If you didn't make the art, then input the username of the artist who did, or if it's off-site, provide the source link and the artist's name. If it's a base that someone else drew but you colored, or vice-versa, you're able to add both artists with the "+ Add Another Artist" button.
Finally comes NSFW settings. If your art is sexual, gorey, sensual, or sensitive in other ways, then you must appropriately mark it. This is just ToS for ToyHouse, and could get your image or entire character suspended if you're not flagged properly.
Editing Your Character
On the left side of your character page, you'll find a list of links similar to this. You'll want to move down to the Control Panel.
Open up "Manage Character". Here you can do a variety of things, such as changing the avatar, editing your profile info, making a tab, or deleting a character.
Tabbing Your Character
Tabs are useful tools. Sub-galleries are shown visually beneath your main gallery and not on a separate page. It's good for storing different outfit styles, or different forms for shapeshifters. I honestly haven't found a functional difference for Basic Tabs and Full Tabs, but if you want a second tab, I recommend Full Tabs because they have more options on the site description. These are good for different AU versions of your characters.
Finally, we have Split Tabs, which work like Full Tabs, except it also behaves as its own character, which can be placed into entirely different folders. This is recommended if the character you're applying for on Arcadia has a separate primary form and you want your own character avatar.
Once your tab is created, save for the sub-gallery, it functions exactly the same as a character folder does, and can be edited through the same method.