If you download a file from TechersPayTeachers it will more than likely be what is called a Zip file, in order to open the files you downloaded you have to extract the files. To do this, locate the file in the downloads portion of file explorer (the yellow folder on your task bar). Once you find the file right click and select extract files. There will be a new folder in your downloads with the same title of the original file, but without a zipper on it.
If you are trying to print a PDF, but it will not print for some reason, right-click the file, select open with, and then select Chrome.