What to do if you decided to install the air conditioner?

It’s hot. Both open windows or fans can no longer cope. There’s only one thing to do — to install an air conditioner. But is it so simple? How to reasonably spend money on installing  „source of coolness“ and install an air conditioner, without causing discomfort to the neighbors. Or what should you do if the outlet and the  extremely loud outdoor unit of the air conditioner installed by your neighbor from above disturbs you?. What are your and your neighbor\‚s rights in this case