Welcome!
Assuming you've already read the Code of Conduct, read on.
Please join our Discord - it's the best place to ask if you have any questions.
To start developing with Besu, you'll want to know how to build from source and be familiar with coding conventions, and how to run the tests locally.
If you're even thinking about making any changes to Besu code, set up your github signoff so you don't have to worry about the DCO check.
If you're submitting a PR, take a look at the contribution how to, also you might need to add to the changelog.
If you're adding a new CLI option, take a look at the Besu CLI Style Guide.