After you have created a sales case you can easily access it by clicking the case name anywhere in the system. When you open a sales case you can browse through sales related data like expected project value and its current status. Sales process an be added and edited in Settings > Sales statuses. There you can also edit different probabilities for each status.
Status can be updated through the Sales overview kanban or Sales tab on a specific case. When you close a deal, Probability is automatically updated to 100% and current date becomes the Expected order date. These can of course be adjusted manually if needed.
You can also track all the past and future activities from sales case. All activities linked to a case are shown under Activities and are easily modified there. Adding new activities (to-do's and calendar entries) and quick notes can be done here and all of them can be found also from customers card's contact information tab.
From Sales tab you can also easily access proposals and files added to it and add new ones. You can read more about proposals from guide Create proposals.