There are many ways to run a node. Here are some.
Tom will write up the setup he uses for GB7RDG here. For now, here's the config file.
TARPN is a prescriptive formula which builds on G8BPQ in order to achieve a certain network topology and very good throughput at the expense of dedicated point to point links, rather than point to multi-point, so more radios.
They have installation scripts for the Raspberry Pi.
If you're sitting next to it, you can do what you want under your own callsign.
If you're planning something unattended for unknown third party use, a-la a voice repeater, you'll need an NoV. These are easy to get but do require some forethought. More to come on this.