Hi Le'Shaunda,
May I know how you are trying to access an existing form from SharePoint? I am not sure if you are opening forms from a SharePoint Library and querying data from a SharePoint list. If so, you may need to add a data connection which queries data from the SharePoint list, add a filter to specify which data you wish to edit, and after querying, set the data from the secondary data connection to the main data connection to display queried data.
The same approach applies if you are using a custom form from a SharePoint list.
Regards,