There are multiple levels of engagement. The simplest is simply to ignore the patent and take the risk.
You can get an independent lawyer to write a finding that the patent is invalid for reasons X, Y, and Z. What this does is to insulate you from treble damages.
There is a formal process for requesting invalidation, but it requires starting with the confidence that the patent is invalid (or a lot of money to waste, or both), and those things are usually enough to justify either of the two above options.
Situations where it makes sense to request formal invalidation seem to be rare.
You can wait until you get sued, and counter with an invalidation action.
I don't think you can DIY any of this. Especially, the rules for what is "obvious" and what actually counts as prior art, are complicated and it's easy to be wrong.