Footprints of the phantoms is a very fun mission. The outpost is fun/easy to capture and once you know the walker locations it serves to be a great easy S-RANK. All objectives were rather simple as well. This makes for a nice cool down from the very hectic and buggy lingua franca mission.
100% Eliminate All walker gears .
100% extract two prisoners from Ditadi Village.
100% Extract all walker gears .
100% Pick a Digitalis (lutea) from Ditadi Abandoned Village.
100% Extract the truck at the start of Ditadi Village.
Eliminating all walker gears is easy enough once you ran through this level and either watch the video or know their location. You can simply use air bombardment on them. Alternatively you can extract and that will give you another mission task objective complete. To the north west of the first two walker gear sets is the Lutea plant/Digitalis.Pick it for that objective.
Finally for the truck and two prisoners. The truck is easy in plain sight once you start at the mission marker. Just extract it , very simple. Next the two prisoners are better found with D-DOG. I would capture the outpost and finish all objectives THEN run through for the S-RANK.