Binary packages are available for Windows systems. If you are on a different system you have to install from source.
If you have problems installing Timeline, send an email to the user mailing list and ask for help: firstname.lastname@example.org.
Installing on Windows
The binary package for Windows installs an executable version of Timeline built with py2exe. It is a self contained executable that doesn't need any other dependencies to be installed.
Download SetupTimeline0190Py2Exe.exe and execute it.
Installing on other systems (installing from source)
Download timeline-0.19.0.zip and follow the instructions in the INSTALL file.