I have been gymming for some time now. Proteins are very vital in building muscles and the amount of proteins you intake is directly proportional to the muscle growth. I am a vegetarian so have to stay away from meat, fish and eggs which are unfortunately for me great source of proteins.
Yet they claim that whey protein supplements, creatine and other stuffs are great source of proteins. On internet they advertise it at a very grand scale with tall claims. Being a rationalist, I researched on it a bit before putting my money on it. So many people claimed it to be fake and just a bundle of lie.

I also want suggestions from the people who have successfully used these supplements to build muscles. Do they really work or not?

These supplements are very poorly regulated and many are very dangerous. You're better off to do your research on meat alternatives and increase the protein sources in your food. I would also strongly recommend that you at least reintroduce some animal based protein back to your diet such as fish, eggs, chicken and dairy.

It is very difficult to get enough of the things you need from a vegan diet with a normal lifestyle, but if you are also trying to bulk up muscle, it's going to be really an inadequate diet unless you are absolutely vigilant about educating yourself about a high protein vegetarian diet.