People have different ideas on how to use certain characters. But here is how I think Aze should be used in a 5 vs 5 battle:

Starting items:
-2x Stout shield
-tango or healing salve

Mid game items:
-2x Vanguard
-Power Treads(strength)
-Mask of Death
-Bracer
-Wraith Band

Late Game Itens:
-2x Vanguard
-Satanic
-BKB
-Power Treads(Strength)
-Bloodstone

Skill Buid:
1. Counter Helix
2. Berserker's call
3. Counter Helix
4. Battle Hunger
5. Counter Helix
6. Ulti
7. Berserker's Call
8. Counter Helix
9. Battle Hunger
10. Berserker's Call
11. Ulti
12. Berserker's Call
13. Battle Hunger
14. Stats
15. Battle Hunger
16. Ulti
17-25. Stats

How to play axe:
Before the game starts, you should go whether top or bottom. Then go through the jungle and stay in between the two enemy towers.(but becareful, be at the VERY centre or die) When the Creep spawn, you will just have to creep walk like crazy. Stay out or trouble and escape when you someone from another lane is coming to help. This usually cause chaos among enemy ranks and is a very good technique if mastered well and catch you opponent by surprise. Other than that, you dont have to worry much because you dont get hurt to easily. Remember, you are the tank of the team.