someone said its when you die and i want someone else to inherit it and another said its "me"?
A beneficiary means one who benefits from something. The benefit may come from an estate, trust, annuity, insurance policy or some similar source. Where there is a will there is a relative. Let us say a rich Uncle likes one of his relatives he will make out his will so that when the Uncle dies the relative he likes will get his money and benefit by it. Thereby that relative becomes a "BENEFCIARY" (Beneficiary)
There are variables and levels of beneficiary to consider, but to answer your question simply, a beneficiary is the person who receives your estate, life insurance policy payments, or other things set out in your will.
So, if you decide that, when you die, you want your little brother to inherit everything, he would become your beneficiary.