You only need resize_sd.sh and install_snapclient.sh

Download both install scripts to a fresh piCore Installation

$ wget https://github.com/bjwelker/Snapcast-piCore/raw/master/install_snapclient.sh
$ wget https://github.com/bjwelker/Snapcast-piCore/raw/master/resize_sd.sh

Make the script executable

$ chmod +x *.sh

Run the SD resize so it´s space enough

$ ./resize_sd.sh

after reboot run

$ sudo resize2fs /dev/mmcblk0p2

Second run

$ ./install_snapclient.sh

After reboot snapclient should play :) To switch betwean HDMI and analog output use

HDMI:

$ amixer cset numid=3 2

Analog:

$ amixer cset numid=3 1

or just connect to the Webinterface on http://SnapCast-Client-IP