Hi @Arcisze ,
Could you please share a bit more about your scenario?
Do you want to edit the selected item in your Gallery, and then save the changes back to your SP list ('GSI Backup Engines Info')?
Based on the needs that you mentioned, I think the Edit form control could achieve your needs.
On your side, you could consider take a try to add a Edit screen (EditScreen1) in your app, within the Edit screen, add a Edit form control (Form1), connect this Edit form control to your SP list (set DataSource property of Edit form to 'GSI Backup Engines Info').
Set the Item property of the Edit form (Form1) to following:
Gallery3_1.Selected /* <-- Gallery3_1 represents the Gallery control within your Screen5 */
within the Edit screen, add a "Submit" button, set the OnSelect property to following:
SubmitForm(Form1)
Within the Gallery3_1 (in your Screen5), set the OnSelect property of the "Edit" icon button to following:
EditForm(Form1);Navigate(EditScreen1, ScreenTransition.Fade)
Please also check and see if the following video would help in your scenario:
https://www.youtube.com/watch?v=yT4gGVunU0o
Best regards,