You may want to take a look at the installation Guide and Getting started guide on our wiki: http://wiki.freepbx.org/display/HTGS/How+to+Get+Started+Home
You can also view our guides on most of the modules, which should be enough to get you a basic installation. http://wiki.freepbx.org/display/F2/Connectivity+Modules
We also have paid support options if your are interested in having one of our professionals, build your system for you. See http://schmoozecom.com/oss-signup.php
Okay, your first decision is where to install FreePBX, Premise (on your own equipment) or hosted (see FreePBXhosting.com)
Sounds like you already made it past this step.
Step 2 Installation, you can install your system using the following instructions http://schmoozecom.com/video/install-freepbx-distro.php (skip this step if already installed.)
Next determine how you are going to provide “trunks” a trunk is basically your connectivity to the PSTN (Public Switched Telephone Network.) or in layman’s terms, how you place and receive calls to and from outside of your phone system. There are several types of trunks, but I’ll assume you are looking to utilize VoIP trunks and not connect to regular phone lines (POTS Lines- "plain old telephone service. A SIP trunk connects your PBX over the internet to a communications provider, each SIP trunk provider will configure their trunk connections a little differently, depending on the methods used to connect to their services. When using FreePBX the easiest carrier to configure will be SIPStation.com because the SIPStation module integrated directly into FreePBX. When purchasing SIP service you will purchase Trunks (which provide the call paths), and DIDs “Direct Inward Dial” numbers, which are phone numbers utilized with a PBX. The DID can be routed using INBOUND ROUTES to a specific destination on your PBX, for example you can have a DID that your companies Main number routed to a RING GROUP that rings multiple extensions at once, or to an IVR “interactive voice response” that gives callers a choice of destinations (press 1 for sales, 2 for support…etc.) and you can have additional DID that point directly to an individuals extension, making it much easier to call them directly.
Once you decide on a carrier and get your trunks set up, you will then want to start building your system, by creating Extensions for your phones, Inbound Routes to point your Incoming calls to the correct place. Outbound Routes which tell your system which trunks to use for different types of calls, for example, when you dial 911 in most cases you will want to send that call out a particular trunk, utilizing a DID that is enabled for e911 services for the address of the location of the phone dialing 911, so you would set up an outbound route just for 911 calling. You then would want to set up additional outbound routes for each type of call you will allow on your system, without a matching route a call will not be placed. So you can set up a route for local, long distance, international and so on. If you don’t want your users placing international calls, don’t create a route for that type of call.
Once your extensions are created you can then connect phones to those extensions, the Commercial Endpoint Manger is a great add-on to your system, as it will do most of the heavy liftion for you when creating extension…
Spend some time in the FreePBX wiki, there are many articles and download 'The more you utilize the system the better you will be at it, if you get stuck you can always post in the forum, you can also purchase paid support to have one of our techs assist with your initial configuration and setup.