Basic info and other screens not displayed in object editor
I have only just started learning the programme and am afraid, I might already have made a crucial mistake, sorry if it was a silly one:
I have created some screens for the standard object editor and I might accidentally have changed 'Basic Info' in a way that it has disappeared from the list of screens I get when I click on an object to edit it. Other screens I created unfortunately are not displayed either, so crucial fields like 'physical description' currently seem to be editable via spreadsheet.
How can I restore the 'Basic Info' and/or get my custom screens displayed?