Link to go back to the earlier node(user input task) from current node(user input task) in Appian

Normally I would design this in such a way that both the "search" as well as "results" would be in one single interface, and would use on-form logic to govern which component(s) are displayed and in what sequence.

Are you required to send an e-mail in between "search" and "results" tasks, every single time any user executes a "search"?  That seems like it'll have the potential to grow to a troublesome volume of emails eventually.  What is the use case here?

To directly answer your question, though: if you absolutely must have these on two separate User Input Tasks, then from the second task, simply add an XOR gateway after that task, checking whether the user clicked the "go back" button, and if so, loop back to the first task.

Normally I would design this in such a way that both the "search" as well as "results" would be in one single interface, and would use on-form logic to govern which component(s) are displayed and in what sequence.

Are you required to send an e-mail in between "search" and "results" tasks, every single time any user executes a "search"?  That seems like it'll have the potential to grow to a troublesome volume of emails eventually.  What is the use case here?

To directly answer your question, though: if you absolutely must have these on two separate User Input Tasks, then from the second task, simply add an XOR gateway after that task, checking whether the user clicked the "go back" button, and if so, loop back to the first task.