If you don't know the rules, here they are.
In the Blue Corner: Huh? There is nobody here. Can you hear hellish screaming in the distance?
The gates open!
Those brave Guardsmen seize their chance and leap out of the gates, flamers ablaze, as a squad of 12 Bloodletters materialise in a small woods before them. Three pistol shots and 6 flamers should make short work of their foes - but despite 20 hits some incredibly unlucky rolling only resulted in 5 wounds. At least these all ignore cover; only one Daemon makes it's invulnerable save.
If at first you don't succeed, charge it with bayonets! The Guardsmen assault directly into the path of 16 daemonic Hellblade attacks. Obviously still in shock from the mid-materialisation BBQ, the Daemons could only manage 8 hits, resulting in 6 dead guardsmen.
The imperial soldiers strike back with 41 lasgun butt attacks leading to 21 hits. With some bad luck this could take out the remaining Bloodletters - but the Guard can only convert these hits to 4 wounds, of which one is saved. Having lost by 3, the Guard look to to their stubborn Commissar and are not afraid.
Round 2 and there are only 5 Bloodletters left, but the Guard attacks are halved without the assault bonus. The Daemons manage 6 hits, wounding (and thus killing) 4 Guardsmen. The remaining 15 Guardsmen (4 with pistols) manage 10 hits and convert this to 4 wounds. Only 2 Daemons fail their save, so the Guard must again test to flee! Once again the Commissar inspires his troops with courage.
We are still going in to round 3, but the daemonic position is starting to look precarious with only 3 left in the fight. They strike first but roll badly, managing only 1 dead Guardsman. The remaining 14 guard can only manage to hit 6 times with their 18 attacks, and even worse cause no wounds whatsoever! In what is becoming a case of deja vu, the Guardsman lost the combat and the Commissar ensured that they stayed around to fight on.
The poor Daemons finally run out of bodies. They can only score 2 hits and none convert to wounds. In return the 16 attacks of the guardsmen cause 2 wounds, and none are saved. Fearless wounds clear out the last Bloodletter.
Aftermath: Without the charge the Bloodletters were always facing an uphill battle. All those flamers should have done a lot more damage - they were very lucky. This inability to convert hits to wounds continued in the first round of the combat. The daemons failed to capitalize on this luck and were beaten into the ground by the Guards superior numbers. Man of the match award to that Commissar, whos "encouragement" kept the squad in the fight - despite losing every round of combat bar the last.