I interpret it this way, and maybe I'm all wrong and don't know what I'm talking about. I base my assumption on the way I think it works in RFactor2. The numbers are a percentage of power. So if I set off throttle to 80%, it means when I lift off, power drops to 80%. This would mean I would slow down slower but have less chance of losing control than if I set it really low and power suddenly dropped to 20% for example. On the other side, a low setting for on throttle would give me less instant power than 80% would so I would be more likely to spin the tires with a high throttle value. In RF2, there's a setting for how fast the change is made, too.
I can't talk about camber. Part of my problem is that I'm so bad that I don't think car setups matter for me yet. You have to drive decently and consistently to get any measure of how good/bad the setup changes are. In a nutshell, I don't drive good enough to appreciate setups.
I really wish there was a free practice mode in F1 2016 where I could test my setups with the current build level of my car.