Yes. Me new too, just like you. I am playing since 1 week.
At the beginning spun off was the major cause of my drivers not finishing.
Even game manual does not explain it properly...so I try to help you a little.
Major cause is loss of traction caused by wrong tyre temperature (not pressure. however wrong air pressure can make wrong wear and temp too)
The slider below the map is not tyre pressure it is about tyre saving. (pressure is different thing in car set up)
Slider is tyre SAVING slider. IF you wear too much it can be an another reason of spun off.
But you are on fresh tyre after PIT stop righ ? Yes ? Did you check ? I sometimes forgot to change the tyre
Game does not do it for you.
So assume you are on fresh tyre without significant wear.
If tyre temperature is not FINE (TOO LOW OR TOO HIGH) chance of spun off is increasing a lot.
When they tyre temperature usually is NOT IDEAL ?
After PIT (need to bring it DOWN to race temp. Yes. Down ! )
Before PIT (if your race well below or above 50%)
You can monitor the tyre temperature if you click on the thunderbolt icon on race management reports
It will take you to the car status (report car in details along with tyre temperature)
Now comes with the confusing part.
After PIT stops tyre temperature will be TOO HIGH.
Logically think you need to warm up the tyre to race temp but actually the game expect you to do the opposite.
AFTER PIT STOP CHECK TYRE TEMP (Actually better to check in every 3 laps during the race)
IF HIGH -> push harder on the tyre, tyre slider ABOVE 50% (EFFECT: Temp should decrease to FINE status)
IF LOW -> save on tyre slider BELOW 50% (EFFECT : temp should increase to FINE status)
As summary you need to keep the tyre temperature FINE (by adjusting tyre sliders) as much as you can.
Avoid TOO HIGH or TOO LOW temps for more than few laps.
TYRE TEMP LOW : DECREASE TYRE SLIDER
TYRE TEMP HIGH : INCREASE TYRE SLIDER
If you manage like this, chance of spun off will decrease a lot.
(Still can happen here and there especially with not skillfull dirvers and many other factors)
Cheers