When adding content pages, agendas, minutes etc. you will want to add documents to those pages.
Method
Go to the Website admin dashboard and click on Media.
Click on Add Media File
Now you can either "drag and drop" a file from your documents folder on your computer or you can click "Choose File" which will open up Files on your computer and you can select the document/image that you want to add.
Click "open" in the dialogue box.
Back in the website admin, you now just need to click on "Upload".