You are able to link files from another fusion 360 file by dragging and dropping the design from within your project folders into the drawing that you currently have open.
You will notice an image of a chain link next to the component (traditionally a part) or component group(traditionally an assembly) that you inserted into the document.
To create a 2D drawing from this design, you will click on File in the top left hand corner and then select new drawing>new drawing from design.
This opens up a dialogue box where you have the following options.
You can either insert the entire assembly or you can choose what components (parts) you would like to detail.
There is only one option for Drawing. That is Create New.
You can create the template from scratch or open an existing template.
The 2 standards you can choose from is ISO or ASME.
The Units are either mm or in.
The sheet sizes that can be selected are A0, A1, A2, A3 and A4 (portrait or Landscape)
If you open that main design in your internet browser you will see that beneath Design References 3 sections. Uses, Used In and Drawings.
The Uses tab will tell you if any drawings are being referenced into the design that you have opened in the browser.
The Used In tab will tell you if your design is being used in any other designs.
The Drawings tab will show you if you if any drawing have been created from this design.