log inPermission to add files is granted only to users that have logged in. You must log in, by entering appropriate username and password in the 'log in' box here on the left.
creating a fileYou should go to the folder where you want to create the file; if you have permission to add files there, you will see a tab "content" or a small tab "add new file" here above: click it! (For example: you do not have permission to add files here.) Click on "add new item"; read the list of file types and choose the most appropriate, and click on 'Add'. This will create the document and bring you in a place where you can edit it.
editing the fileThese following are the steps to do for editing the file.
uploadYou should upload a file. Click on the "edit" tab, click on the "Browse.." button, choose a file, and click on "save" on the bottom of the page.
metadataYou should provide good metadata. Didn't we tell you how important metadata is? :-) Unfortunately you cannot edit this file. The job will be done by a reviewer.