How do i go about getting all my mothers things she passed away and didn't have a will

If there was not will, you will proceed under administration of the estate.   This is filed in the local probate court.  If someone else caused the wreck, you likely will also have a wrongful death case that you could handle as administrator of the estate.  There is a priority in the law as to who can file to be the adminstrator, but if you are the next of kin, you can open the estate 5 days after the death.