1. All-In-One APRS Transmitter (by Justin Kenny) *recommended
2. Right now the most commonly used APRS Sats are AiSat-1, PSat2, ISS (when APRS is operational), and NO-84. (https://www.overlandbound.com/forums/threads/aprs-via-satellite.25928/)
3. Simply set your standard APRS setup over to the Satellite frequency (Generally 145.825MHz Simplex), set your path and away you go. Remember however that because the satellites are in orbit, the window in which the satellite will be visible will be small. LOW power is to be used - the satellites will hear you (http://www.aprs.net.au/satellite/aprs-satellite/)
4. To work the satellites, your path must be set to digipeat via ARISS,SGATE,WIDE2-1 ARISS is a common alias used by the Satellites, and SGATE is required in order for a recieving SatGate to pass your position report into the terrestrial network, and WIDE2-1 is the path used once the beacon is in the terrestrial network, and should be enough to reach a normal VHF IGate.
5. Add ISS Packet Operation to Your Satellite Activity (http://www.ariss.org/uploads/1/9/6/8/19681527/k9jkm_2012_symposium_ver2.pdf, https://link.storjshare.io/jvbmvxwn5z6ryriaaineia4eys7a/demo-bucket%2Fk9jkm_2012_symposium_ver2.pdf)