A Long and Dangerous Road

You have to escort the convoy until you reach the base where they keep the rest of the bavarium tanks. In the first stop, take out the foot soldiers and the elite soldiers on top of the arch. Once done, ride along the convoy until you reach the first second checkpoint. Enemies will appear from the ruins so use the explosive barrels beside them to take out multiple targets at once.

Once that checkpoint is cleared, ride along the convoy once again and take out any pursuers sent your way. Use your grappling hook to tether the pursuing jeeps and shoot down the motorcycle riders. When you reach the second checkpoint, you can tether the gate instead of using the gate controls. Cross the bridge and continue repelling the pursuers.

Escort Mission

Later on, a tank will be dispatched to chase after the convoy. It will be easier to hijack the tank and use it against them. After reaching the second bridge, you can either close the gate or blow up the bridge after the convoy passes it. You need to get rid of the tank sooner or later so when an enemy helicopter appears, hijack it and use it to provide cover instead. Keep protecting the convoy until you finally reach the base. Kill the remaining soldiers and activate the EMP to trigger a cutscene and complete the mission.