Download all the things we need (I suppose you have python, pygtk and libvte installed):

 $ wget
 $ wget

Unpack them:

 $ tar xzf dynagen-0.10.1.tar.gz
 $ tar xzf gdynagen-0.1.4.tar.gz

Put all the needed things together in one directory:

 $ cp gdynagen-0.1.4/gdynagen* dynagen-0.10.1/

Now get a dynamips binary and put it into the dynagen directory:

 $ wget
 $ wget

 $ mv dynamips*.bin dynagen-0.10.1/dynamips

Run gdynagen!

 $ cd dynagen-0.10.1
 $ ./gdynagen