The Library List allows you to drag symbols of products into your document. To insert a symbol just click once on the symbol name, drag it into your document and release your mouse button to place it. Do not doubleclick on a symbol name to insert it - this will instead open the actual symbol file for editing.
The 'My Libraries' root is where you can save your own user folders and symbols. Rightclick and choose New Folder to create a user folder, and drag a selection into your user folders to create a new symbol.
The 'Offline Libraries' root shows the Stardraw symbols that are downloaded into a local database when you Synchronize Manufacturers. You can hide folders in Offline Libraries (rightclick and select Hide) but you cannot delete or change these folders or the symbols they contain.
The next level down from the Library List root is the Environment Root ('Blocks', 'Pictorials' and 'Racks'). each of these folders contains symbols libraries designed for that specific environment - you should always be sure to use the right symbol for the right environment.
When you start a new document the Library List will change to show symbols from the right Environment Root.