Tampon help?

I've never used tampons b4 and i want to try them. Idk how long to keep it in tho. I hafta change a reg. absorbancy pad about every 2-2and a half hours. I have reg. ab. tampons and it says the absorbancy range is 6-9 grams. idk wat that means. help. also how do i dispose of the tampon, my mom doesnt want me flushing them down, should i put it in a little plastic dixie cup and throw it in the garbage can? plz help cuz im a little nervous