To use ASDM, you need to enable the HTTPS server, and allow HTTPS connections to the security appliance. All of these tasks are completed if you use the setup command.The security appliance allows a maximum of 5 concurrent ASDM instances per context, if available, with a maximum of 32 ASDM instances between all contexts. WebVPN and ASDM administration cannot be enabled on the same interface. If you enable WebVPN on an interface, then that interface cannot be used for ASDM.

Uset the below commands for configuring ADSM:

hostname(config)# http source_IP_address mask source_interface

hostname(config)# http server enable

hostname(config)# asdm image disk0:/asdmfile

Refer the following url for more info:

http://www.cisco.com/en/US/docs/security/asa/asa71/configuration/guide/mgaccess.html#wp1047288