How was my step mother able to sell my fathers home her left to myself, my half sister and two step sisters.

Have a will that states my father leaves his real property to the four of us kids which we would get remainder of his wife. His wife a year or so later sold the house and bought herself a condo and my step sisters are getting the condo and my half sister apparently got everything else left. I was not privy to copies of my father asset distributions of which I was a beneficiary and heir to a portion, nor my step mother's and don't know where to begin although I do know my father was worth over 1.5 million dollars.