@jhonnmick Lindon is right, you will want to spend most of your time looking at the SlotFx API.

I've shared one template on how you might handle this here:

https://forum.hise.audio/topic/12723/modular-fx-template-changing-fx-order-with-drag-and-drop-panels

it's fairly recent but may be outdated now, as the most recent update of HISE contains a dynamic container which is well suited to this task. If you pull from the recent developer branch on github you can experiment with this (I haven't yet).