Ideally you just need to search the repository of your distribution for packages named logjam with your installation tool, select that and your Linux will do the rest. Or with the apt get method described on that help page you'd just try "apt-get install logjam" for example.

It's only hard if there is no pre-assembled package for that program, but usually even compiling isn't problematic if you have a new distribution and all relevant libraries plus the C compiler installed. Then you download the source and follow the readme file.