Workflow Actions will be carried out in the order they are listed, which can be important.
For instance if you want to Send an Autoresponder from a Support Ticket being opened, which details what Department and Queue the Support Ticket is in, you want the action which sets the Department and Queue to run before the action to send an Autoresponder.
To change the order in which the actions will take place, grab the action handle and drag this to the position you want: