you tell me what is the salary of a cleaner and waiter in krakow ?
It is very low. Too low for you to be able to live and to pay off your airfare to Poland and your visa fees. But that is beside the point. You would never get a visa, because no hotel or restaurant is going to go through the trouble and expense of getting work permission for a lowly housekeeper or waiter from Bangladesh, and the work office will not issue work permission because there are already tons of unemployed Polish people who would be eager to take the job. So you would never be granted a visa to Poland. You would be wasting your money even trying.
Sorry, but your plan of coming to Poland is completely unrealistic. Forget about it. Wages in Poland are far too low to make such a move worthwhile.