Imposition question

[Pam Christofferson]

can any one help me...I have Fp 5.8 and using CS3. I am trying to "n-up pages" I have two different 8.5x11 pdf's that I want on a 12x18 sheet. i.e. 1 and 2 so I want 1,2 on one form. Right know all I can get it to do is step and repeat. 1,1 &2,2 on two forms.

Any help would be appreciated

thanks,
andy