How do I install extensions for caja?

I am still very new to how linux files work, especially how things run and install.

I found caja extensions I want on github but I have no idea how I would install them or which files I should download. Can someone help me understand this?

Here is the github page I was looking at:

This is already installed by default so you don't not need to install it. If you want to check run sudo apt install caja-open-terminal for example in terminal to see. To install extra software on your system use Software Boutique. Caja extension exists in official repository so you don't need to use github.

I use synaptic for installing, and recommend it.
Sudo apt-get install synaptic
Here are the addons available:

I think they should meet your needs.