As well as building action buttons on the form or in the command bar, Automation Actions can be created against form load events. Common form load actions include setting values in fields, running a script, or directing the focus to a specific tab. Again, these actions can be conditional.
The form load events include pre-form Load and after-form Load:
Pre-Form Load
Actions defined in the pre-form load will fire before the form itself is rendered. This is an ideal time to use the action builder to define variables, or to execute custom script that is required.
After-Form Load
Actions defined in the after-form load run immediately after the form is rendered and the controls on the form are all visible. This is an ideal time to use "Redirect to Tab", or to set values within fields.
In order to configure form load actions you need to click on the "Actions" button in the skybow command bar. Select "Form Load".
Now you can define pre-form load and after-form load actions for your SharePoint form.