1) Check the API docs first. Terminal ctrl contains regular topic++ files for TheIDE. It should be available through TheIDE's help system.

2) Create a CtrlLib application (basic or with layout, it's up to you. Terminal ctrl contains a layout file, so you can use it in TheIDE's layout editor.)

3) Add Terminal ctrl to you app. As it is a regular ctrl, it can be added to your window or any other "parent" ctrl via Ctrl::Add() method.

4) If you are going to use it as a local terminal, using a pty (currently on POSIX only), then Terminal package contains a PtyProcess class.
   Add #include <Terminal/PtyProcess.h> to your app. Then all you need to do is set up the events and loop.
   Provided examples use a rudimentary loop which is sufficient for most cases but you can write much efficient loops that'll suit your personal need and use-case. 

5) If you are going to use it as a GUI front end for, say, SSH shells, add uppsrc/Core/SSH package to you app, and connect the loop. See the rudimentary upp-components/Examples/SshTerminalExample