On client side, each user will have to run a signed program named “Setup-ConnectionClient.exe” as a pre-requisite.
This program is available on your server, in the RDPlus program folder: C:\Program Files (x86)\RDPlus\Clients\WindowsClient:
It is also available in C:\Program Files (x86)\RDPlus\Clients\www\ConnectionClient, so your users can just run the program once on your web server address: http://xxxxxxxxxxx/ConnectionClient/Setup-ConnectionClient.exe
Alternatively you can download it from here.
Note: Since RDPlus 12.40, The Client Setup Program and the RemoteApp client setup have been merged and can be deployed with one single setup – so if you download the Connection Client Setup, there will be no need to download the RemoteApp Client one.