Home Forums Mac Software Mac Operating Systems upgrade from Lion to El Capitan

I will be helping a friend upgrade her MBP from Lion to El Capitan. She can, of course, download EC herself and keep it In /Applications until I get there, but I may be able to save some time by downloading it to my computer and transferring it to a USB Flash drive. I have read many articles about creating a bootable installation disk but that's not what I want to do. I merely want to bring the USB drive to her and then run the installer.

My question: If I download the EC installer and then copy it to the flash drive, will it work in upgrading her OS? Should I copy the installer to her hard drive before installation or will it run from the flash drive?