How can I see how many customers I have?

You can easily see how many contacts you have in the system, by navigating to Contacts in the left-hand menu:

Then you will be able to see the following all at a glance:

1.All Contacts

2.Current Customers

3.Past Customers

4.Leads

Custom View:

You can also see how many contacts you have in each custom view by selecting any custom view from the dropdown:

And then scrolling down and looking at the total on the bottom right.