The DevTools are currently in heavy beta as they are pretty difficult to get right and provide the correct insights. It will need to be used by folks and get feedback before it can be distributed on the Chrome Web Store.
Chrome is the only supported browser at the moment.
Before you can install the tools you will need to enable the developer mode in the chrome://extensions . You will see this toggle on the top right. Once you do this, you will be able to load unpacked extensions.
Getting the extension installed can be done in three steps.
Clone the repository
This will get you the source code that will need to be built.
Build the project
Load the unpacked extension