Hi @adamrichards, welcome to the Community. Qubes OS is a very different system than others. You do not install or run any software in the AdminVM (dom0): You only use it to manage virtual machines.
Here is my super-short introduction to Qubes:
When you boot into Qubes OS for the first time, you will have the following virtual machines for your service. Sys-net contains drivers for your WiFi card and connects to the network, so it’s untrusted by default (don’t run Firefox there!). Sys-firewall protects you from DMA attacks and allows to use the Firewall rules in Settings of other qubes. Sys-whonix provides Tor connection to anon-whonix (in which you should run Tor browser). All connected usb devices go to sys-usb qube by default, to protect you from USB attacks. If you need to connect them to other qubes, use Qubes Devices widget. Vault qube has no network by default, making it a good place to store your secrets. With personal and work qubes you can separate your private and working lives by running related things in them (e.g., two independent Firefox browsers). See this for an example.
You should install software in TemplateVMs: How to install software | Qubes OS.
If you have any questions, feel free to ask here or create a new topic.