Rumble 40 is a nice little practice amp 👍
In annswer to the second part of your post. There are lots of online lessons and what have you, some free some paid. StudyBass.com is one of the best free sites, especially for getting the basics right. That means a proper position so you don't injure yourself and understanding what a bass can do musicaly (other than sound awesome).
Scotts Bass Lessons has a lot of free stuff which is good. His style is a bit manic, but what he says is spot on. The subscription works out just under £100 per year, or four face-to-face lessons, and is also structured well. Getting a few face to face lessons is well worth it at the start as well.
The one thing that will make more difference than anything else is playing with other people. Hard at the moment, but seriously nothing beats it.
Enjoy the ride. I've only been playing a couple of years, work gets in the way of practice, and I can't play with the band as I am the sound engineer. So I am utterly carp compared to where I could be, but still enjoying myself. Rock on with Paranoid!