Solid Floor to Wooden Suspended floor quandary.....

[LondonLad21]

Evening all.

I am doing a home extension, myself, that's slowly come on over the past few months.

I poured a solid concrete floor onto insulation, and the kitchen diner I have created has a combination of the new floor and old wooden suspended.

How do I build the finish over the old cavity wall that I have taken down?

Thanks in advance.