IASM, Direct Video Adressing, & TP7.0 HELP!?????

I really need help on the best way to use IASM... (internal assembler), or
to write code that will use DVA.  I am framiliar with the standart ASM
statements and am well experienced in TP 7.0.  If there is a FAQ or a book
outhere, or someone kind enough to help... please respond.
        Thank you,
Tony Mahar