First you should register so you have an identity here. Click here and then continue after you're registered under what you want your name to be here. Don't use your real name and avoid names that are similar to someone else's. Don't forget to log in here to make sure your edits get recorded as being done by you.
Next, start your userpage. Type "User:(name)" into the search box on the left. Click on the red link to create it, and then type in some information about yourself. Don't forget to click save. You can add pictures if you want, or whatever you like.
You can start a new page with whatever name you want by typing it in the search box and clicking the red link, and then typing in your content and clicking save.
You can also put a link to the name of the page on another page so you can find your new page. Type in [[name of your page]] anywhere you want people to be able to get to your page from. If you don't do this, you might forget where your page is, so link it from your userpage or any other pages you think a link to it should go.
Images and sound filesEdit
To upload images or sound files, click on "insert image" at the top of an editing screen (which you can get to by clicking the editing tab) and use the browse function to find your media file on your computer. Then follow the instructions. You can insert a link to your file by typing in [[Image:(name)|thumb]] where you want it. For sound files, put a direct link to the actual file so people will be able to download it. This may be a little tricky, so ask for help if you need it.
Having a problem doing something? Ask for help here.