|That is one of the easier things to answer.
Assuming your web browser can load a PDF (if not, see the FAQ regarding that question), near the top of the frame that displays the PDF has many little icon type buttons, one of which one is for PRINTING the PDF.
The print icon/button to click is the 4th from the right-hand margin at the top. It should look like a little printer.
And for multi-page PDFs, assuming you have a page to go FORWARD to (obviously, the last page of a PDF has no following pages) or a page to go BACK (obviously, the first page has no prior pages), you will see an UP ARROW (for going back 1 page) and a DOWN ARROW (for going forward 1 page) that will be available to click to use instead of scrolling with your computers mouse (as shown below):
You can also see that the other iconified button functions also seen in that same upper frame is SEARCH, MAGNIFY (zoom-in), De-Magnify (zoom-out)E, DISPLAY FULL SCREEN, DOWNLOAD, plus a menu on the right-most icon that will display all of the different functions if you click to show it.