Place the dynamic microphone directly in front of one speaker of the guitar amplifier cabinet. Given the flat response of a dynamic microphone placed so closely to a speaker, you'll avoid picking up ambient room noise such as unwanted reverb that is created by the amplifier sound bouncing off the walls. The placement will result in a sterile recording.
Place the condenser microphone approximately two feet away from the cabinet. The microphone should not be placed directly in front of the cabinet but off to the left or the right. This will not only pick up the sound from the amplifier. It will also record ambient noise including the room's natural reverb.
Connect both microphones to a mixing board and combine both microphones into the mix. Lowering the volume of the dynamic microphone will allow for more ambient reverb to be present in the mix. Reducing the volume of the condenser microphone will result in less ambient tones and yield a sterile guitar tone. The volumes of each microphone should be manipulated until the desired guitar sound is achieved.