When you print from another program and you click on the print button you should see a pop up window that shows the printer that you will be printing to. Here is an example of one of the printer pop up windows from one of our computers -- the printer will not be "Named" the same as in this example.
If the name showing on your computer matches the name of the printer you are trying to print to, record that name so you can connect to it when you try to use in in Horizon.
For printing receipt options open up a Checkout window and you should see a "Tools" tab click on that and you should see "Change Receipt Options
Looking at this window you can set "Allow Printing of Slips and Receipts" and "Allow Emailing of Check Out Receipts". Below that you have the option of printing various different receipts. The most common ones are shown here.
Finally you'll see "Windows Printing". This must be checked and if you click on "Setup" you might see a list of printers available to you. Select the printer with the same name as the printer you use to print from other programs.
The first time you use it you might be asked to select a font. Most likely you can just leave at the default settings, just click on OK in the font window. If you make the font too big text will not fit well on the page when printing the pull list or other reports.
Finally, the second place you might print to is from the Menu column.