Buildable makes it really easy to pass data between steps. To do so, you'll use the key-value table found in the step you're looking to assign data.
Let's say you're building a simple Recipe that generates a Random Code and you want to pass the data from the Trigger step to the Function step.
To do this, simply add a Key name (i.e., name) and use the drop-down selector in the Value column to assign data from a previous step (i.e., $steps.trigger.name). Keep in mind, you can also manually type
$steps in the Value field to assign your data faster. You can also type the value statically (i.e., Jane).