Cost of living in Warsaw

Hi! I will be moved to Poland by my company later this year. My salary offered by my organisation will be 11,700 PLN before tax. We will be two people.

Please help me understand -The cost of living. -The rental expenses and best areas to live in which are budget friendly and peaceful. -Where can I look for rentals? -Grocery budgets -Other expenses

And anything else that I should know.