[Serusers] simple click-to-call

Hello, As an exercise in learning how all this stuff works, I'm trying to set up a simple click-to-call service for our office to use. And potentialy to allow clients to use vai the web site to save them on the long distance charges. I set up Asterisk with the TACI script and got it to all work with an account on gafachi but I noticed that it could only handle one call at a time. I was told that openSer would allow more than one call at a time so I've installed it (basic no mySql) and have it up and running. Now, being new to this I have no idea how to connct to gafachi and do a click-to-call type thing. Would anybody be able to help me with this? Regards