To set up a sales process which specifies all the basic steps or activities of a sales process, you follow below steps:
1. Go to config icon, and then company settings
2. Go to Default values, see Section "Our processes"
3. Click on the green plus icon button (+) to create a new sales process and follow instruction.
4. A new sales process is created with red warning symbol next to it that mean the creation has not completed yet. You have to add or edit the steps (activities) so that all the steps add up to 100%, which is when a sales process is completed.

You can also drag and drop the steps/activities to rearrange their order in the list or edit the percentage of each step as the way you want