So the essence of this build is to pick talents that are best for team fights. The Vikings do a surprising amount of damage when focusing a target, but their weakness is getting picked off. The secret is to group in such a way where Olaf can go in first and them be ready to run any member away individually if they are getting focused. My preference is to run in and immediately pop the Viking longboat, which currently does a very large amount of damage. Try to steer the boat around the edge of the fight so that you can constantly barrage the enemies without getting blown up. When the boat ends all of your vikings should be near full HP. Remember to use "Jump!" to dodge high damage abilities and activate "Norse Force!" early, preferably after the boat when you run in. Save your "Z" for cleaning up a fight or for a quick escape. Try not to use it to initiate, as your are squishy and not the best initiator.

Vikings can easily clear merc camps, just remember to have Olaf tank and all three helping to clear quickly. Olaf heals very quickly when out of combat, so if needed rotate another in to tank temporarily, but in general, keep Olaf as the tank.

At the beginning, STAY TOGETHER. Once you get good with the Lost Vikings you can experiment with splitting, but my advice would be to have them work as a team until you're experienced with them (level 8 or above). The exception to this is when you run a viking back to base to heal, which I'd recommend occasionally as you can hearth each back separately.

So if you don't want to mess with all of the abilities you can go for a decent build without all those pesky abilities (see my right click to win build). This build is also decent, but I don't think the vikings are able to survive as well with it.

Level 1: Block on Olaf is ok, but I believe Viking Horde to be the better choice because it allows all the Vikings to gain HP and enter most fights with full HP! Spy Games is only rarely helpful, wort pick IMO.

Level 4: It's Sabotage can be ok if you want to micro Erik a lot, but not useful for team fights. Heardheaded Redhead is great in team fights if you want to micro Erik like crazy to get behind enemies, but still much harder to use. I prefer Spin to Win! as a straight damage boost. Pain Don't Hurt is ok, but not great. Only use this if you want to pair it with the lvl 7 talent Baelog the Fierce.

Level 7: For team fighting pick either Jump! for survivability/dodging or Baelog the Fierce for straight DPS. Erik doesn't need the extra healing if you already got Viking Horde.

Level 10: Longboat Raid! for sure!

Level 13: I prefer Hunka' Burning Olaf for the dps increase, but all are viable for team fighting.

Level 16: All of the talents here are ok, but I strongly prefer Norse Force! for team fights unless they have very heavy CC, in which case 64 KB Marathon is ok.

Level 20: Ragnarok n' Roll! of course! HUGE dps boost in team fights!