How to create a website with Joomla
Configure the user settings:
From "Global Configuration" select "System". There you can change the front- and back-end options for your users as well as allow registration to your site. From here you can determine the session time as well, so you would not be automatically signed out of Joomla in every 10 minutes. From this menu you can disable particular file types, set file size limits for uploading etc.