http://jenkins.cyanogenmod.com/
You must be a member of the CyanogenMod organization, and your membership must be public at https://github.com/CyanogenMod
Jenkins will authorize using OAuth to GitHub.
Click the "android" job.
Configure what you want to build.
Build it. Note that regular builds (nightly/snap/whatever) can only
be produced by the automated processes. Manually triggered builds will
always be labeled as EXPERIMENTAL
Edit cm-build-targets and submit a pull request. The syntax for that file is documented in its first few lines