Advice for extending the CMS in SS 3

Silverstripe Version:
3.7.0

Question:
The best way to extend CMS to run custom reports and data object management?

Hi Guys,

I am trying to extend the Silvertripe CMS to build a support console for our clients. However not all functionality involves managed models as per the Silverstripe docs. I was wondering about the best way to add purely custom forms (ie not related to any specific DataObject or controller).

I have a custom SupportAdmin.php which extends ModelAdmin. However this requires $managed_models to specify what appears here, when not everything I want to add relates to a specific model.

For example we have a large amount of records called “Brands” eg (Coca Cola, The Beatles, Nintendo etc) which extends DataObject and I want to be able to bulk import large batches with CSV but also handle a number or options and child relationships at the same time.

So what I’m basically looking for is the best way to add completely custom sections to the CMS. Any guides, sources or tips for SS3 would be greatly appreciated.

One thing in particular I’m interested in is loading in custom templates to the CMS. Any way to do this in 3.7?