If you are attempting to print things such as receipts, appointment lists or other items and nothing is happening then it is likely that your browser is blocking popup windows. The exact way to fix this varies according to which browser you are using, and the version of that browser.
To find the correct way for your browser, we recommend doing a Google search for "allow popup windows in [my browser]" replacing [my browser] with the name of your browser, e.g. Chrome, Firefox, Safari etc. This should deliver the correct information.
If you get stuck then please send us a support request. We're happy to help!