Where is the best trading tutorial on the forum or on the web we can find?
GOOGLE SEARCH or your favorite search engines. There are lots.
It's kind of spoonfeed if someone will teach you from the scratch. Just asked questions on steps or stage where you are having difficulty.
About asking how to used trading platform just learned the interface and basics. Different exchanges have different interface but the principle is just the same. For specific instruction, just mentioned your preferred exchange.