Let's assume that you have at least a couple of fields in your tickets: a category field (which could be "email" or "laptop" or other things), a timestamp and a sourcetype of "ticket". Finally, let's also assume that tickets have a field named status, which could contain "new", "closed", etc.
Here is a very simple search that will show the volume of tickets opened over time, by category.
sourcetype=ticket status="new"
| timechart count by category
The more fields that you have, the more fine-grained your possibilities for searching and graphing. But - if you don't have fields to categorize the data, it will be harder. You could use eventtypes to help build categories, but it will be a lot of work if the variation is great.
For example, I could create an eventtype based on the search "Outlook" OR "email", but that might be too broad or too narrow for the data. Tags can be helpful for categorization, too.
You can find information on tags and eventtypes in the documentation. Here is a short video tutorial on eventtypes; it is several years old, so the user interface looks different, but eventtypes are still the same.
