Whats needed to undertake to create a Fire Evacuation/Fire Safety Plan for a purpose built block of flat (with commercial spaces & a car park at the basement)

If you need to ask such a question maybe your not the right person to conduct such a task and need the help of a qualified person. But if you want to understand more about the subject check out https://www.firesafe.org.uk in particular page https://www.firesafe.org.uk/fire-emergency-evacuation-plan-or-fire-procedure/.

You also need to study Fire safety in purpose-built blocks of flats and having commercial spaces & a car park at the basement does complicate matters.

Thanks