Go to Settings > Sales settings.
This is where you can set up:
The stages in your sales process. You can reorder them or add new stages here.
Set up lost reasons so that you can say why precisely you lost a certain opportunity. Some typical examples would be:
We're not the right fit
They decided to go with another tool
We were too expensive
Timeline was unrealistic
Default deal probability
When creating a new deal, this is the default probability that will be assigned to it. You can read more about deal probabilities here.