Do you mean that when a user presses a button on Form1, it disappears and Form2 opens.
From Form2 he can press two buttons - "Back to Form1" or "Show Form3" in which case Form2 disappears and the appropriate form is displayed? And that something similar happens with Form3?
If so, the way I would do it is to have a Hidden "parent" form, which takes requests from the three "children" and controls which instance is displayed at any one time. These requests would be in the form of Events which the "Parent" would handle, and hide and show the appropriate form instances. Sound Complex? It isn't - it's actually really simple!
Have a look at this: Transferring information between two forms, Part 3: Child to Child
] - it's more generic than you need, but if you read "information" to means "request to show a different form" then you should get the idea.
Typos: "Form" for "from" and "your" for "you" - OriginalGriff [/edit]