How to use more than one mod on minecraft?

Not necessarily at the same time, but just in general. I just recently figured out how to actually get mods on, but now I'm having problems. I downloaded pixelmon as my test mod. And it worked. But the video had told me to delete everything in my.minecraft, and save it to a folder on my desktop as backup. Then I used the 1.6.4 forge. I also wanted to use the mocreatures mod. But when I added it to my mods folder, (the same mods folder pixelmon was in) and then created a new profile on minecraft, with the forge as my version, it just took me straight back to pixelmon. I would love to know how to use more than one at a time, example, mocreatures, and maybe a mod that adds items and ores and such. Both at the same time. But I'd also like to know how to use them one at a time, please help!