I wanna start a podcast but i have no idea how, where should

Audacity and SoundCloud? I honestly have no idea, but those two are free. I don't know if iTunes is or not, but it might be the more popular option. Also, I have no idea how to promote your podcast other than maybe facebook and youtube. Anything like that where you can add tons of tags and get in on relevant. You can probably also find video software and just feature images over your audio podcast, that way you can tag your videos and get added in with relevant videos from other people and also turn on advertising on your video if you want a little change in your pocket. Believe me, it will literally only be change unless you get really popular. Just get out there and try it out. Try shit out and see what works well and what sticks.