There is no right or wrong with amp settings because there are at least four factors at play: 1) how the amp is voiced along with its controls, 2) the electronics in the instrument/pedals and how they interact with the amp, 3) the physical interaction between you and the instrument, and 4) your own preference for how you should sound.
The amp itself will have a specific voice that is baked in by the manufacturer based on their own goals. This could be due to preferences of the amp designer, based on market research for a target customer, or perhaps to meet the needs of an artist that works with that company. The controls can vary widely across amps even in products from the same brand. Some only cut (attenuate) the signal while others boost it and each control (bass/mid/treble/etc...) will be centered around a particular frequency which differs quite a bit. Also, some controls interact with electronics in ways that aren't intuitive such as how the mid-range and gain is done in an Aguilar Tone Hammer or how low-end is added when boosting gain in various Marshall amps.
Another consideration is how far you can push an amp before it starts to distort or clip. Again this goes back to the overall design goals. The Ampeg SVT can be pretty clean at low volumes but starts to get the "dirt" or "grit" that people love as you crank it. A Hiwatt on the other hand will make you deaf before you get heavy saturation. The electronics in the signal chain also play a role since you can add things like a on-board preamp (active pickups) or use pedals which can push the amp harder than just the instrument alone. And don't let passive pickups fool you. I have some basses with passive pickups that are almost as hot as an active circuit.
The last part is really the most critical. How you play and your own sonic goals will completely dictate what you should be doing. Are you wanting something super loud with clear and articulate response? Or do you need an ultra fuzzy monster that can be tamed in your bedroom at 2am without having the police show up? If you want to sound like John Entwistle you'll need a lot of treble and learn how to percussively attack the strings like he did. I'm not sure what the secret sauce would be for Geddy Lee but a lot of it will come down to his hands so you'll have to figure out how to adapt your technique to be more like his while also paying attention to how this sounds through the gear you have. Or maybe you just want to do you own thing so some experimentation is needed.
Anyway, the TLDR of all of this is pretty simple: just sit down with your amp and start turning the knobs. Make sure to turn them all the way from lowest to highest. Pay attention to how each control individually affects your tone, volume, and overall sound. Pay attention to how the controls interact with each other and try different combinations, even if they don't sound exactly like what you want. Keep doing this until you play more than you turn knobs. That's when you know you got it right.
As they say: "If it sounds good, it is good."
