Connect a Form to a SharePoint Calendar accurately using Flow

I have an automation where my users can fill out a Form and Flow picks up the fields and puts them into a SharePoint calendar. Now when Forms populates the calendar list, it is one day early for every event, I think due to there is no time field in Forms. I'm trying to add a day to the date fields in Flow by using the adddays formula, but I don't know how. Can anyone help me, or think of a better solution?