Locate the stereo outputs or "Main Out" connectors on the mixing board. The stereo outputs will be located on the mixer's back panel, and require an RCA connector. The "Main Out" connectors will be on the face of the mixing board, and require a 1/4-inch audio cable. Purchase an RCA to 1/8-inch cable for the stereo outputs, or a 1/4-inch to 1/8 inch audio cable for the "Main Out" connector. Connect either cable from the RCA or 1/4-inch output on the mixer to the 1/8-inch input on your laptop.
Purchase a digital recording program for your laptop. Many recording programs can be purchased for free online. Follow the program's download instructions from its website. Locate and launch the downloaded recording program from your laptop's operating system. In a Windows machine the program will appear in the "All Programs" menu in the Start menu. On an Apple laptop, the program will appear either on the desktop, or in the "Applications" folder.
Go to the physical mixer and turn up the volume on the channel where your speaker's microphone is connected. If the person delivering the sermon is using a wireless lapel microphone, have him turn it on first and have the volume at a reasonable level. Go to the virtual mixer screen in your recording program. Press the record button on the program, and have your pastor begin speaking into the microphone to test the overall recording level in the recording software. Adjust the volume levels on the lapel microphone, physical mixer and virtual mixer accordingly.
Press the "Record" button on your recording software a few minutes before the worship service begins. Press the stop button once the service has ended, and save the recorded audio file to your laptop.