The Hero in Soldiers Inc

How do i rank up the Hero. 

I wanted to equip a rare item to my Hero. However it was refused and system required my Hero gains experience before i can use that equipment. 

Please explain how i can achieve this for my Hero.

How many hero can I use. 

Will my Hero bonus apply to both attacks if i send 2 attacks at the same time to an enemy base. 

Please can you provide tutorials for every new design. A Hero tutorial ..A Cobra tutorial etc...Right here on the forum. 

Thank you 

Me Selfridge Aka raging bro