Question: need to update from Yosemite to El Capitan
I need to migrate files between older MacBook to MacBook Air. The older one is running El Capitan. The newer one is running Yosemite. I can't migrate because the old one is running a newer OS apparently. I can't seem to get the MacBook Air to get to El Capitan. I have downloaded El Capitan from web and when I try to update, I'm told it can't go from 10.10.5 to El Capitan. What to do to get from 10.10 to 10.11?
What to do so that I can do the transfer of files between computers?
MacBook Air, OS X Yosemite (10.10.5)