First you will need to create a document of your project. Learn how to quickly do so here.
Once you have a document created and ready to go here is how export it as a PDF:
Click the Export/Share button in the top right corner.
A dialogue box will open where you will select Download PDF.
A PDF of your document will then be downloaded onto your computer to use as you wish.
Here's a quick video showing you how to do it:
