My AC blows warm air
GARRISON 2498545

The image below from the amazon link. 

The area in red box is where air from your room is drawn into the unit. It passes over the supercooled coil and exits back into your room through the top vents. Do not obstruct air flow into the unit. Set mode to cool,energy saver off, temperature to lowest 62, fan to high. 

And if there is a setting or manual method fir opening a vent to let outside air into the home close it. Amazon page describing this unit photo below. 

Take note of the feature called air exchange. This would be a feature allowing the option of introducing fresh outside air into your home during the cooling cycle. Obviously you want that off on very warm days.  

If all of that still does not give you lots of continuous cool air there us something wrong with the unit and it needs to be serviced by a qualified ac technician