Read the detailed installation instructions.
Quick installation instructions:
1. get the file
grass-5.7.0-DD-MM-YYYY-arch-bin.tar.gz
2. get the installation script
grass-5.7.0-DD-MM-YYYY-arch-install.sh
For installation, run the install script with --help option:
grass-5.7.0-DD-MM-YYYY-arch-install.sh --help
Get this file.