I'am not good at trading honestly , I basically only sell goods or buy them , mostly sell them and just hold my BTC so I'am not sure how all this trading story works ...  but as I start I'd like to know how much the minimum amount needed to start trading with so it's possible to make a decent profit from it ? (Don't recommend me of gambling because I won't)

I may also take a look at this : https://www.udemy.com/bitcoin-trading/ but I'am not sure how good is it .