Modify brochure

I have to modify the N. 100 page A4 already made ​​from horizontal to vertical or brochures in tri-fold. All files are format A4 format must be the same but change the shapes and positions of images and text. All file are made in Pages for Mac. All file are in one page with images and text Required: Front page must be original Back page must be original but only with the background All file must be change from vertical to orizzontal in tri-fold brochure All file must be in A4 and ISO MEASURES so don't change the actually measures All file must be save in Pages (original) PDF ready to print,JPG,WORD windows