To create a segment matching contacts based on their behavior in previous sendouts your first select the channel (or any) under Channel behavior in the add-pop up.
On the segment workspace, click on the dropdown to select the interaction criteria:
Select the sending module, e.g. Campaigns, for your selected interaction, or pick Any if all modules should be taken in consideration.
Narrow down your segment by selecting a specific (e.g.) Campaign or something in a specific project.
Under expandable Show more you can set more details for your condition. Depending on the interaction you've selected, the option may vary a bit.
Here you can set a timeframe for the interaction and number of interactions.
Only set criterias under Show more will be displayed when re-opening a segment (or clicking Show less).
Let's take a look at an example. In below segment we want to target all contacts that have clicked at least once in any email campaign sent in the project Deals SE during the last two weeks.
The clicked link must have been tagged with the link categories garden and design.