Install the required packages:
$ sudo pacman -S apache perl perl-cgi php php-cgi php-apache
Download the application code, put it to the server directory, and configure:
$ sudo git clone https://github.com/CSAILVision/LabelMeAnnotationTool.git /srv/http/LabelMeAnnotationTool
$ cd /srv/http/LabelMeAnnotationTool
$ sudo make