- [*] Hold Hill 317
- [*] Defend Town of Mortain
- [*] Rescue the Ranger Patrol (reward: Army Expert Badge)
In this mission you have to hold hill 317 [*] for 30 minutes, you can't let it to fall into german hands. 
Previous hill owners left a system of trenches on it. Don't jump into the trenches for the moment but move downhill: create first line of defence under the hill as game suggests (the hill will be your last line of defence, your Alamo - you will withdraw to it when Germans start pushing you stronger). But first, man with your soldiers three AT guns you will find on the hill between the trenches (fourth has a crew already), marked with big white dots on my map, and two HMGs there (small white dots). Hurry up because timer over the minimap starts ticking. 
Move downhill with these AT guns and HMGs too, try to place them as you see on my map for example. You can leave one gun on the hill as a reserve but don't roll it to the northern edge of the trenches because that spot will be shelled with german rounds several times before Krauts start their attacks. Try to set up rest of your AT guns perpendicularly to the direction enemy vehicles will come from (you'll see infantry first), to shoot at them from the sides, but this is not always possible. Place some sandbags wherever you can, in front of your HMGs and AT guns, build OPs on points that are closest to expected directions of German assault. 
At the same time you can sand somebody (an engineer and HMG teams for example) to the abbey [*] on east - one Ranger squad is defending themselves there, besieged by two german squads and MG-42 team. Try to rescue that Ranger patrol by flanking Krauts from behind (from the graveyard) and you will receive suitable medal for your help and these Rangers armed with bazookas will join your forces then.  But leave'em there when they're safe (hop in to the building again with'em), capture abandoned MG-42 that left after killed Germans and also leave it there (place behind some low wall) - Krauts will try to recapture the abbey later.
Meanwhile (more or less) you will see first Germans on the road leading from the north - some infantry squads and Pioneers. Withdraw these few Americans that spotted Germans to the HQ, there is no sense to fight with outnumbered enemy.  Replenish the manpower of this small unit and use it later.
When Jerry starts his assault he shells the hill with his artillery several times (as I mentioned). His target: northern edge of trenches system.  You can roll closer (to have an eye on hill's approaches) your AT gun located further to the rear only after these barrages.
Earned command points spend on possibility of placing sandbags with your riflemen first, then - on your own off-map arty support. 
Eliminate Germans attacking at the same time from several directions (marked with red arrows on my map) with your HMGs and AT guns fire. If you see too many enemies use against them your howitzer located on the hill, don't hesitate also to shell them with your off-map artillery if you already have this possibility. 
Krauts assault with few waves: they send infantry first, some motorcycles, snipers and MG-42s later, halftracks Sdkfz 251, armoured cars Sdkfz 234 and PzKpfw IV tanks at last. 
In some moment during the fight you will receive secondary task - to defend town of Mortain located southern [*] from german attacks. However, to complete this goal one armoured car Greyhound (produced in nearby factory) and an engineer team (repair task) should be enough because Jerrys will attack from west (in time intervals) with rather small forces: two infantry squads first (one of them armed with Panzerschrecks), then a halftrack. Kill them all one by one, starting with soldiers with Panzerschrecks. 
In the abbey further to the north (at the left (west) edge of a map), where your rescued and left Rangers Patrol, you'll will see a gunfight too. On the abbey-yard will occur some assault gun Stug IV with company of few soldiers. Your captured MG-42 should cut enemy infantry to the pieces and Rangers armed with bazookas can deal with enemy vehicle. 
When the enemy starts pushing harder and more and more of allied soldiers fall dead it's time to think about withdrawing to the trenches on the hill 317. Withdraw there what you still can, first of all your AT guns: you can leave HMGs behind to slow down pursuing Germans because you can produce some more later, in your weapons support depot located on the hill. So recruit more HMG sections and also infantry squads in barracks on the hill and place them in the trenches. Kill Germans running and driving uphill with all you've got, don't even hesitate to throw sticky bombs at german vehicles. 
Shell enemy infantry climbing up the hill 317 with your howitzer rounds and using off-map artillery. 
Try to collect with your infantry Panzerschrecks you can see sometimes after killed Germans and use them in your fight against enemy tanks coming from several directions.  When timer over the minimap counts off last seconds from 30 minutes you had to defend hill 317 this mission ends successfully.