If you are working with the PRO or Enterprise version, that is the functionality of a CRUD and in fact the system creates what is necessary by itself. If this is not the case and you are working with the community version:

1. You should have created the form and the related list.
3. You must create an access to the LIST in the userview and assign it a custom URL (eg listform1)
2. You must create an access to the FORM in the userview and put a custom url (eg form1) (this access can be hidden but not restricted in privileges). Within this configuration you must also configure that once the system is saved redirect to listform1
3. In the list, you must create a hyperlink in the right area of the list that points to listform1 and sends the id parameter with the ID field. Additionally you could create a button (to create a new record) with a similar configuration but that nevertheless does not send the ID parameter (similar to what is shown in the image below).

Hi,

Can you please explain more what you mean to create access on step 2 and 3?

Maybe to just add the form and the list?

Instead of updating it is inserting new record. but I just want to update existing record.

Try this: APP_crudComExample-1-20210211081509.jwa