In MS Word, if you click on File > Options, then click on Add-Ins, you should see 'Microsoft Dynamics GP Add-in for Microsoft Word' listed under the Active Application Add-ins.
If you don't see it, or it's under the inactive add-ins, at the bottom of the Add-Ins window, next to 'Manage:', select 'COM Add-Ins' and then click Go..., here you'll see a list of add-ins that are available. Find and mark the Microsoft Dynamics GP Add-In for Microsoft Word, then click OK, which should at least add it to the list of inactive add-ins.
When the add-in is enabled, in Word, you'll see a 'Developer' tab (which you may also have to manually add to see it in Word) and under that Developer tab, will be a 'Microsoft Dynamics GP Templates' section, with buttons such as 'Field List', 'Add Source' and 'Remove Source'.
