Patience definately - I've just taken the dash out of my 72' and the manual states installation is a 'simple' reversal of the removal process.
There was nothing simple about taking it out, but the key was perseverance (and a lot of cursing and tea to make me feel better).
Lying diagonally on the seat, legs in the air, head in the footwell was interesting - Take a cushion with you......Its not too comfortable down there.
A ratchet spanner is a must!
Good luck.