Hi Kalwant. So here is the info for uploading a PDF. I uploaded a pdf about culture to test.
In the + ADD tab, go to Buttons, and scroll down to Document Buttons and you'll see the icons.
Clicl to add a PDF, and then it will prompt you to the Upload page, where you can choose the PDF file from your computer, and then click to Add it to the Page. Once it's there, click the icon and the Settings gear and check Show Title.
On upper top right, Click Preview, and the page will open up to how it's seen live. Click on the icon and it should open.
Go back to Editor, save and follow the prompt to Publish.