There are several scenarios around disk layout so some more detail would help. Do you have a clean partition or some unpartitioned space to use as a root volume for Arch? If not then you may need to shrink or recreate the other Linux partition to free up some space. This can be dangerous but I think gparted can make it easier/safer.
Much of the legendary Arch Install Guide still applies, but you can probably skip grub-install and be sure you know which partitions are going to be used for what and which ones need to be left alone.
Grub-mkconfig should just work when there are 2 Linux OSes installed and set up boot options for each one.
Never heard of EFF but 0 points for being 10 years late on this very easy and obvious decision.
There are several scenarios around disk layout so some more detail would help. Do you have a clean partition or some unpartitioned space to use as a root volume for Arch? If not then you may need to shrink or recreate the other Linux partition to free up some space. This can be dangerous but I think gparted can make it easier/safer.
Much of the legendary Arch Install Guide still applies, but you can probably skip grub-install and be sure you know which partitions are going to be used for what and which ones need to be left alone.
Grub-mkconfig should just work when there are 2 Linux OSes installed and set up boot options for each one.