From the dashboard, go to the "Conditions" page and click on "New condition".
Start by giving the condition a name. This name will be useful for using the condition in other places.
You will then have this interface which allows you to create conditions. A condition is created by combining an element on the left with an element on the right.
To take a concrete example, let's imagine that we want the user to be logged in to complete a report. To do this we will simply select "The user" at the top of the left hand list, then "[BASICS] be logged in" at the top of the right hand list. Once this is done, you will see a block appear as below.