There is a HUF already with you and siblings and mother. Open bank account and other accounts after getting a HUF seal.

There is nothing like a registration for forming HUF unlike partnership.compnay formation.You can write a declaration for HUF consisiting its members,karta and the property you are intending to form in HUF.For more authenticity you apply for a PAN card in the name of karta mentioning his as a karta of HUF.That's it.