First, install the Technic Launcher, downloadable from www.technicpack.net.
Sign in with your Minecraft user name and password.
Select "Add New Pack" from the left-hand menu bar and copy in the following URL:
http://www.technicpack.net/api/modpack/erbosoft-plus
This will install the Erbosoft-Plus pack alongside any other modpacks you wish to use (even vanilla Minecraft).