Chen
welcome to Pprune
In the Wannabees forum there are a lot of experienced pilots who are happy to help a person get a first foot on the ladder.
However they do expect people to have done a little research of their own before posting here. You will find that nearly all the questions you ask have been asked - and answered - many times before.
As has been suggested, please read the 'sticky' above where you will find some of the answers and the rest can be found using the search function.
In the meantime I shall close this thread and let me have a PM when you have more questions.
HWB