The answer is: No can do.
Rethorical question - how are you going to launch the installer?
An advanced user - not a beginner - would consider a network tftp server to serve a boot image from which you could launch the installer. But Manjaro doesn’t support such scenario.
Technically you could use an Arch pxe boot image to start your system - then change the mirrorlist to point to a Manjaro mirror and do a hands-on manual installation.
Such task is for a skilled and highly experienced user - not something I would recommend to a beginner in Linux.
It’s doable but it requires hard work and dedication to learn.