You're on the long and winding road! : )

808's MIDI OUT (Make sure it's not set to THRU) to Fantom's MIDI IN. Set 808 to transmit MIDI Clock (I prefer this over MTC for better measure cueing.) Set Fantom sequencer to SYNC to MIDI Clock. Press play on 808, and the Fantom should start right up as well. Record on it and play back all in perfect harmony with your 808. (Best to insert a 1 measure blank before song starts on Fantom and 808 to allow a good sync up.)

Hope that can help you some? It gets pretty heady from there.