Dirt bike knowledge on kx 250?

My friend is selling his kx 250 dirt cheep, and i wana buy it, but i dont wana test ride it and look like a fool, the only bikes ive ridden in the past was a rmz 125 and a crf 250f, any knowledge or info on how to start riding on the bike successfully, such as how hard i have to hit the g, would be appreciated. Thanks