To play this mission first you have to choose option
Truth: Solovetsky. It's Solovetsky when playing the mission Identity Crisis, when Adler asks you where Perseus is.
Recommend firing more than one grenade at a time, 2 or 3.
When approaching the monastery just after the emp explosion you will need to take out all the towers and truck on the approach.
6 x Towers
4 x Trucks
In order:
2 x Towers both sides of the road.
1X Truck just behind left tower (left)
1X Truck opposite side of the road (right)
1x Truck opposite side of the road (left)
1X Truck opposite side of the road (right)
2 x Towers left both sides of the road.
2 x Towers just up ahead, blow these before animation starts. If you missed any before animation starts, restart check point.
Slow motion video for additional help: