The latest version of pre-built Open GApps can be found at https://github.com/opengapps/opengapps/releases
If you want to build your own version of Open GApps, you'll need to get the git sources:
To initialize your local repository using the Open GApps source tree, use a command like:
git clone git@github.com:opengapps/opengapps.git
Then sync the submodules to get the original APK sources as provided by Google. You can also use this command to update at a later moment the sources to the most recent version
./download_sources.sh
To build Open GApps for all platforms and all android releases:
make
To build Open GApps for a specific android release on a specific platform, define both the platform and the API level of that release, seperated by a dash. A (most widely used) example:
make arm-22
One can update the sources used with the command:
./add_sourceapp.sh /path/to/the/file/you/want/to/add.apk [/even/more/files.apk...]
For contributors, updated sources can be uploaded by browsing to one of the sources-subdirectories and pushing it to the repository:
cd sources/architecture
git add *
git commit
git push