I have a rooted Nexus 5 running CyanogenMod 12.1-20150510-NIGHTLY-hammerhead. I created a new user from the top right corner, but it didn't have gapps installed on it. When I try to install, it only replaces the one on the original account. How do I install it on the second account? I have TWRP Recovery
It should've been installed by default. If it hasn't then there is something wrong, do you see the play store if so go to the play store and install the other Gapps.
I think it's because you need to setup the space seperately. So you need to install it from there.