Resize root partition

[Businux]

Are you able to install and start Gparted ?

https://clearlinux.org/software/bundle/gparted

as @nayab pointed out :

How do I install using premade partitions

Right now the installer detects unallocated space (not empty partition). Delete the empty partition on which you want to install the OS and then hit the refresh button. The installer should detect it. But again the installer creates it’s own swap and esp partition. I tried this way and I am unable to access my old Linux distribution.