Setup localhost mac install for offline editing & mods

I have installed a VirtualBox Ubuntu instance on my MacPro today.
I want to install all of the necessary applications to service all the dependencies that enable Mastadon to run inside my developer localhost Mac.

A month ago I installed a VPS on Linode. Created an Ubuntu 20 instance.
Because I saw a Linux tech recommend Cloudron as an easier install for a Mastadon instance I did that – installing Cloudron and then through that installed an email app and finally Mastadon from the main repository.

So I now have that Mastadon main repository version installed and viewable at a ".de " URL.

But I want to understand the ins and outs and how to modify the styling, etc.

Which is why I want to have a localhost environment on my MacPro where I can work on development and see the pages in my browser on my development machine. And to see the files, open them, and have GUI admin access to the PostgreSQL database.

I see Configuring your environment - Mastodon documentation and I am overwhelmed.

When I setup my Ubuntu at linode vps it gave me some of my needed environment.
Cloudron installation then gave me more and finally the Mastadon package available at Cloudron finished up my installation.

If I want to duplicate as closely as possible all the dependency resources of my online Mastadon installation (as I just described) in my Mac’s VirtualBox installation, then an Ubuntu 20 installation there IS THIS a good direction to start?

And is there a more or less automated Mastadon package that installs the needed environment into my VB instance of Ubuntu?

So that I can then fire up the Ubuntu Admin Dashboard to finish setup?

Am I making sense so far?

Thank you!