Apple/Mac will work basically the same way, Jack. Right click the printable thread sheet that pops up when you hit the "Print" button Steve describes and choose "Print page" or choose Print from the computer's "File" menu on the Menu Bar, very top left of your screen. On an iPad, when the printable thread page appears, the square with an arrow in it at the top right will take you to a menu that contains a "Print" link to your printer if it's on the same network. Relatively new to Macs but not iPads, I was combobulated that without a mouse my then new MacBook wouldn't right-click, so I got an $8 mouse that solved that issue; then I learned that "control" together with a touchpad click was the "right-click" function on a MacBook.
The Forum's "Print" button brings up a printable format, but like many sites it doesn't actually provide a printing function built in; i.e. it can't print itself. That's why you searched the printable page but couldn't find a way to take it to the next step... printing it. Instead you must tell your computer or other device to print that printable page, just as you would most other webpages or documents. So use the the old "right click" or other menu option your device provides. In general but not always, "right click" has meant bringing up a menu that has operative functions that can do something with whatever page you right clicked on. It has long been a feature of both Windows and Apple machines.
Joel
Addendum: Steve, maybe a simple "How to print a thread" feature should be added to the Forum Assistance/Operating Guide or other appropriate section, basically about right-clicking a printable page brought up by the "Print" button.
