How can one find flats?

There are groups in Facebook

Zero in on your target complex. Either thru Google maps, your coworkers, or just walking thru the area. Every apartment complex has a notice board where they put up rent availability details. Ask the watchman he will give the details. It will either be the home owner or broker for that apartment.

There are a few WhatsApp groups that I'm a part of. Listings are directly from flat owners. The only downside is that the units get rented out in less than a day.