You are aware of for eg these https://frappe.io/docs/user/
To manage your changes you best use a code repository for eg App Development using GitHub · frappe/frappe Wiki · GitHub
The web has many howto docs with best practices…
This is good. I missed getting to this video, thinking it was only meant for separate app and not customize existing forms, reports, etc.
As somebody else has indicated that installing your custom app is the key and then you have to export the customizations / set the print formats to the module named after adding the custom app.
I am now fine with the knowledge, and understand this well.
Thanks, this also helps a lot after you have gone through a few trials on your own.
Since Frappe and ERPNext are so interwoven and people who are used to it do not differentiate much, for newbies it does become daunting to see Frappe all the time and then get confused why is it inter-used. I guess this is part of learning about ERPNext.
Kudos to the great community support that is available.