DPK mid-tier only install - How do I then get data into Existing DB?

I read through all of the documentation and it looks like I can use the DPK to put the file where I want on both windows and linux. And hopefully will allow me to set the appropriate users on Linux.

How do I then get the PUM data into our existing DEMO database?

Can I just replace our DEMO DB?

Is there a pluggable database I can put in?

DMS create DEMO database for FSCM?

How do I do this with DPK process?. There doesn't seem to be any documentation on this scenario even though the doc specifically mentions Mid-tier only install to existing DB.