Suspension & set up help

[Ilikeearlgrey]

Guys, I need some help and seem to be getting conflicting advice and it's confusing the hell out of me. I have 2 way shock absorbers, Bump and rebound and need to know what each adjustment does to the handling in layman's terms and what adjustments to make in what circumstances

Rebound - what exactly is this, is this the strength in which the shock goes upwards from hitting the bump, ie, the more rebound the stiffer the shock. What does changing this affect

Bump - What exactly is this, is this how fast it comes back down and how does changing this affect handling.

Also, on longish progressive fast corners the car sort of bounces across rather than turning progressively, it doesn't feel as if the weight distribution is bad, but it's clear from the onboard camera that it's not a smooth transition, what needs adjusting.

And, I have understeer going in and a tad of oversteer coming out, i suspect it's me too early on the power but am I right in thinking that I should go stiffer on the rear springs?

One more question as well regarding tyre pressures, I still can't get to the bottom of this. If it's cold or wet I have always increased pressures and reduced them when it's hot, but i've been advised that I should be doing it the other way around, any views?
The car is a 1100 kg saloon