What?
Already said that. First cellular life forms.
How?
By the purposeful arrangement of cell’s building units.
When?
That can be answered when we discover the age of first cellular life form.
Who?
Cannot infer from biology alone and I don’t wish to speak outside of it in this thread. Maybe in another thread.
Essential genes involved in the synthesis and processing of macromolecules alone constitute more than 300 genes. Along with DNA, cell simultaneously needs proteins & rna molecules to process the information in the former. This is universal to all cellular life forms that is known to us. Based on this information, we can only make informed guesses on the complexity of first cellular life.
Provide emperical evidence for your claim.