Welcome to E&P!
There’s a list of resources here to help with various questions that you might have… that said, since I built up about 200 or so of its pages, I’m rather partial to the wiki. 
There’s also a ton of stuff here on the forums. The Player Guides section is well worth a glance through if you find yourself with a little time to burn some day.
As for your current team… lookin’ good! You’ve got a great intuition! Layla and Needler are great 2* snipers, Bane is definitely your beefiest hero and well deserving of the tank position, and Sharan is pretty squishy and definitely should be out there on the edge.
A good general rule is to have someone with high defense and health in the middle, your supporting peoples on their flanks, and to have fast mana snipers on the edges. That’s for your defense team, though… for your raid offense teams you’ll want to customize your squad to counter the heroes that your enemy has in THEIR defense team. It’ll be a little while until you have enough heroes to effectively do this - it requires that you have a little bit of a bench first.
For the map, your team is golden. Keep an eye out for Olaf or Hou in the short term… they both give your entire team a whopping +63% defense when fully leveled. Sha Ji is also a great upgrade from Sharan. Sha Ji + Olaf was a great combo to run with.
The Teams page of the wiki has some solid basic info about team composition if you’re itching for a little more in depth analysis. 