Question [Q] How do I get from my old ROM/firmware to the latest firmware safely + newer ROM?

I haven't updated my phone in over 7 months. Baseband version, which appears to be old. I see warnings on installing new firmware without flashing intermediate versions. I'm using custom ROM stock with Goodies 2.10.

How do I get my phone up-to-date on firmware and using a newer custom ROM without brickage?