Asterisk PBX coupled with Siemens 3800

Vicidial I installed, everything works and I make internal calls but my problem is this: I have an E1 and Siems 3800 I want to configure outgoing and incoming calls via the PABX Siemens
Now I do not know exactly what files to configure asterisk and how the side or the side to Siemens,

Please help me make sure, because it seems urgent

Thanks for your help