The best to start with are one of the old games. Black and White are good but they arnt the best place to start seeing as you wont know anything. Same thing for Heartgold and Soulsilver. If you can find them try to go for either FireRed or LeafGreen or even Gold and Silver(Which are pretty close to HG and SoulSilver but you dont have the generation 3 and 4 Pokemon.) Start with either of those so you can start to learn Pokemon and thier types. Its always best to start with the basics.