Accessing your available forms
All users can see a list of forms that are present in the stories they have access to on the main Dashboard as shown below:
The forms are displayed with the story image, making it easy to select the form you want.
Simply click the form to launch it.
Users can also access the forms within the the forms tab if they have Edit/Admin permissions.
An additional route to access the form is that it can be placed in a widget via embedding. This would allow viewers to access the view in-story.
Or you can also access a form directly through a form URL, perhaps that has been sent to you by the story owner.
Completing and submitting a form
It couldn't be easier; just follow the prompts, enter your responses and click submit to create a new/edit an existing item in the story.
Remember, however, that although you may be able to access some forms, you can only submit them to create new items if you have Edit permissions to the story. (This requires you to have an active paid subscription), unless the form allows use by Viewers/Anonymous which is determined by the story owner/admins.