How to prove a will invalid?

File objection to the "Will" on the basis of difference in the facts/details about the land as per the schedule attached with the will in the probation suit, also challenge the will on the basis of force/fraud committed by the uncle for obtaining the will in his favour even though for the portion of the grand father which is 1 acre not 2 acres as also other all the mismatches clearly show the haphazard manner in which the will was drafted & got registered that too without the knowledge of other sons of the deceased grand father show force/fraud being committed by the said son objecting the mutation of the property.