Create a new action and call it getNow. There is no need to define any in- or out-parameter.

In the script section, place the following script:

var current = new Date();
System.log(current);

Create a new workflow.

Drag a Sleep task onto the schema and create the SleepTime in-parameter as input for the workflow.

Add the getNow action we have just created before and after the Sleep task.

When running the workflow, check the log. You will notice how the workflow will wait for the allocated seconds.

Create a new workflow.

Drag a Wait until date task onto the schema and create the waitDate in...