Windows

1. Install Caesar III(c) game
2. Unpack CaesarIA game to disk:/games/caesaria/
3. copy .sg2 and .555 files to disk:/games/caesaria/resources/c3
4. copy .map files to disk:/games/caesaria/resources/maps
5. copy .smk files to disk:/games/caesaria/resources/smk
6. copy .wav files from CD disk or ISO image to disk:/games/caesaria/resources/audio
7. go to disk:/games/caesaria
8. Run updater.exe, which downloads all necessary updates
9. Run caesaria.exe

Linux

1. Install Caesar III(c) game with wine
2. Unpack CaesarIA game into /home/user/games/caesaria
3. go to CaesarIII(c) instalation dir, usually /home/user/.wine/drive_c/Program Files/Sierra/Caesar III
4. copy .sg2 and .555 files to /home/user/games/caesaria/resources/c3
5. copy .map files to /home/user/games/caesaria/maps
6. copy .smk files to disk:/games/caesaria/resources/smk
7. copy .wav files from CD disk or ISO image to /home/user/games/caesaria/resources/audio
8. go to /home/user/games/caesaria
9. Run updater.linux, which downloads all necessary updates
10. Run caesaria.linux

Mac

Thanks for Anakros from habrahabr.ru

1. $LIBDIR=~/Library/Frameworks/
2. $mkdir caesaria
3. $pushd caesaria
4. $curl -C - -OL http://downloads.sourceforge.net/project/opencaesar3/bin/caesaria-0.5-macos-build-LAST.zip
5. $unzip caesaria-0.5-macos-build-LAST.zip
6. $chmod +x caesaria.macos && ./caesaria.macos

Update resources exclude executable files

Run updater with --no-exec flag, for example

./updater.linux --no-exec