I have heard that when I die I can dispose of my tangible personal property with a separate written statement. Is that true? If I can do this whatare the details.

When a relative dies (hence the "Decedent"), there is always an issue concerning what happens to the relative's tangible personal property.  Tangible as the name implies is what you can see and touch.  Examples of tangible personal property include the furniture, the Decedent's jewelry, guns, coin collections, paintings et cetera.  Disputes can arise when a Decedent dies and the tangible personal property has not been secured.  Frequently, potential heirs have the view that "finders are keepers" and valuable tangible personal property can disappear.   What is interesting is that the personal who converted the tangible personal property always has justified why that person is "entitled" to the property. 
Tangible personal property is treated somewhat uniquely under the Florida Probate Code.  For example, under Florida Statute §732.515:

A written statement or list referred to in the decedent's will shall dispose of items of tangible personal property, other than property used in trade or business, not otherwise specifically disposed of by the will. To be admissible under this section as evidence of the intended disposition, the writing must be signed by the testator and must describe the items and the devisees with reasonable certainty. The writing may be prepared before or after the execution of the will. It may be altered by the testator after its preparation. It may be a writing that has no significance apart from its effect upon the dispositions made by the will. If more than one otherwise effective writing exists, then, to the extent of any conflict among the writings, the provisions of the most recent writing revoke the inconsistent provisions of each prior writing.

This allows a person to on a piece of paper to dispose (transfer) their tangible personal property without going through all the requirements of signing a will.  There are several requirements here.  First, the written statement or list must be referred to in the decedent's will.  If the statement is not referred to in the Decedent's will then any statement disposing of the decedent's tangible personal property must be executed in the formalities of a will (i.e., the executor executes the will at the end in the presence of two witnesses who then sign the will in the presence of the testator and in the presence of each other).  But what if a written statement is referred to in the decedent's trust?  Then if the written statement is not executed with the formalities of a trust, then the statement is void unless the statement is also