The shortcut button in Slack (lightning bolt icon) can be used to quickly find and use your Slack actions and apps.  It can be found to the left of the message field.

Clicking on the shortcut button will bring up the shortcut menu. 

If you don't see Workast in your list immediately, you can either scroll down or use the search box and type in "Workast" to locate it. 

The shortcut button allows you to:

Click on the links to learn more about task creation in Slack and the forms integration.