Alan Halls 

When you have your file open in the editor you should see this:

Click on the preview button over there on the right.  If you don't see it then you may have closed it... so click on the "View" tab and then "Preview" to put it back:

It'll probably appear somewhere you don't want it, but you can move it to wherever you like:

https://multifarious.filkin.com/2013/10/24/moving-windows

You didn't mention what kind of file you are translating so if you have a problem seeing anything it could be because of the filetype... some require a bit more work on your part or your customers, and some don't have a preview of the final formatted output at all.

I showed a Word document and if you want to zoom it just hold down the Ctrl key and scroll with the mouse while hovering over the preview pane.