You can choose between three diferent routes:
Ruta 1: Madrid historical
Ruta 2: Madrid modern
Ruta 3: Madrid monumental
Each bus will pass 15-20 different spots and you will be given information in English about them.
You can combine 2 or 3 routs and pay less if you make them the same day.
My tip is to make 1 or 2 of the routes in the evening and you will see the buildings enlighted which is very beautiful.
There are some stops when the bus take up and leave passengers and you can leave the bus whenever you like.
Of course those tours are not in any case detailed, but you will get familiar with some of the orientation points in Madrid.

