The initial attack and the defense circa 9 April 1941

 The initial attack crossed the Yugoslav frontier with each division being a column. They moved towards Skoplje. The 73rd Division advanced towards Velos. The Germans moved into Skoplje on 7 April. The German 2nd Armored Division neared Strumica. The Yugoslav defense had collapsed by this point. 8 April saw the southern Yugoslav defenses were defeated and there were only remnants of units in existence. What I take to be the Leibstandarte Adolf Hitler division turned left and moved into the Monastir Valley. The 2nd Armored Division had by this time moved through "the Axios Valley" towards Salonika. 

 The Metaxis Line was a very strong position with well-designed forts. They resembled the Maginot line in France. The Germans had hoped to move through to Salonika, but the forts were not a push-over. The Germans had two mountain divisions and heavy artillery. The Hellas Fort held out for 36 hours after a heavy artillery bombardment. The Ekhinos Fort "held out for days" after the Germans had bypassed the fort and left it in their rear. The Germans had broken through to Salonika, but there were Greek forts stubbornly resisting in the German rear. 

By 9 April, the 2nd Armored Division had reached Salonika. On the left side, two German divisions had succeeded in passing the "frontier forts" and had reached the sea. The Germans had collected some shipping, including Italian destroyers and had "occupied the islands of Samothrace, Thanos, Lemnos, Mytilene, and Chios". 

"During the night of 9 April, British infantry found themselves covered in snow. There were refugees moving through the pass. They observed some Yugoslav troops and Greek police accompanying the refugees. The Greek police were well-dressed in contrast to Greek soldies who were not. 

New Zealand armored cars had driven north and had seen two German columns. One column was at Vevi and a second was at Sitaria. They were lucky to not be damaged, since they had "exchanged fire" with German forces. British air reconnaissance had seen many vehicles sitting north of the Crna river. They were stopped by blown bridges. This is based on the account in "Greece Crete and Syria" by Gavin Long.