I have basic knowledge on Mathematica, but not familiar with if, for other loops and conditional functions. I have to work on a project which involves developing a package something like FeynCalc. There are so many literature available that I feel like getting lost which book to consult. Can anyone give a book reference from where I can start learning the basic structure of Wofram language for a beginner like me. Thanks in advance.
They don't make it easy to find but I highly recommend all portions here that are relevant to your needs. That is an online version of The Mathematica Book. I don't think they print hard copies of it any more, but you might be able to get a used copy if you insist on reading a hard copy. After you finish with the above use this as a reference.