How do you change a Serpentine belt on a 2000 Suzuki Vitara with a 2 liter engine?
It's not so hard. Open the bonnet and face the engine. Note the routing of the belt, draw it if you won't remember.
There will be a smooth (no grooves) pulley towards the top middle. Below this to the left is another smooth pulley. The belt should run over (on top of) this one. It is the belt tensioner. To loosen the belt, place a wrench or socket at the 12 o'clock position and turn it clockwise about a quarter turn. This moves the tensioner pulley down away from the belt, loosening the belt. Remove the belt. If the belt is not broken, remove it by working it carefully around and below the radiator fan, between the fan and radiator.
To put the new belt on work it around the fan in the same way. Route the belt over all the pulleys except the tensioner (using memory or the drawing you made earlier). Again loosen the tensioner using the wrench or socket and slip the new belt over the tensioner pulley. Check the tension.