Add my cesium js code to the terria map project

Hello , so I am totally new to terriaJs I started with cloning the Terriamap project and i got the hang of customizing and charging files into the map .I was previously working with CesiumJs and would like to take that same code and implement it in terrimap project only I have no idea how or if it’s possible to begin with , I just want to create a js file with all the things I want in my map or modify some file if possible (or if there is another way …).

Here are some code I would like to have in my terria map: