Any idea/process to follow for proceed with network segmentation with IT and OT mixed together?

Hi all,

i did a lot of search about this topic but it's still not clear to me to how proceed.

So first of all my job is to separate IT network from OT network as mentioned in a lot of normatives/standards and security best practices.

The network that i have to segmented at the moment is all-in one network with devices, servers, surveillance, and ICS.

is there a process to follow step-by-step? or i have just to separate network elements used for IT and used for OT?

did i have to separate them based on functions? or locations? or both?

thanks in advance!