OK ... this is a good place to start ...
http://www.selintra.com/docs/cgi-bin/view/Main/WebHomeDo a bit of reading up on how to setup the system etc.
Then go here ....
http://www.selintra.com/docs/cgi-bin/view/Main/DownLoadPagesYou need to download the Asterisk rpms and the Selintra Sail rpm.
In short:
After you have loaded the software go into your server-manager and find the SAIL PBX section.
Setup your Globals section.
Then setup your trunk lines .... Click on New Trunk and there is a drop down where you can select one of the pre-done trunks.
If you want an outside line you either need an SPA3000 or a PCI card ..... I have an SPA3000 and works well.
The docs have all the answers you may need to setup the SPA3000.
Once the Trunks are setup you need to setup the Extensions ... either phones or soft phones
You can now setup your Routes ... Rules for what Trunks they use etc.
These steps will get you going for a standard fast setup ... the rest you will have to play around with if you want queues, messages etc.
Do a bit of reading first to get familiar with the interface etc.
Also do searches on here .... there are a lot of answers on setups etc.
Regards,
Tib