Hey Juglad, welcome to the Ranger Station Forum!
There are 2 bolts on your 2.9 that you need to loosen up to remove the tension. The first on is right on top of the alternator mounting bracket you will see a bolt thats tightened up against it and a channel thats about 6 inchs long, you loosen the mounting bolt and push it down that channel to remove the tension on the alternator drive belt. The second bolt is on the idler on the right hand side of the engine, the one closest to your brake master cylinder. You apply leverage to the idler and it should release the tension from the other v belt. Any other questions feel free to ask!