I always think it's a good idea to start with the webinars, there are a couple of getting started videos at the top. Also Ade did a number of excellent videos for FUSE ESB 4. Simply click on the Demo Videos tab of the FUSE ESB 4 documentation. James has a short video in the FUSE Mediation documentation.
In short if you want to do Routing use the FUSE Mediation Router for this. If you want all the benefits of OSGi with for deployment and patching then you should deploy your routes into FUSE ESB. This would be the normal approach to starting with FUSE.
If you have any specific questions you can always post them here and we will do our best to get back to you. Hope you enjoy working with FUSE