The roles are a bit different in DotA since the heroes are divided by their primary attribute(strength, agility, intelligence) and roles. The main roles are carry, support, jungler, but there are also other roles like nuker, pusher, initiator and durable(tank) which usually fit in with one of the main roles. For example, Lina, is listed as an excellent nuker, but does not have the carry role listed and she is more often used as a support. There are multiple setups for the lanes as far as 1-1-2-jungler is concerned. Since Dota has a safe lane(bot radiant/top dire) and an offlane(top radiant/bot dire), the solo player can go in either lane depending on the hero played and the team comp. Usually there is a carry in all 3 lanes or 2 carries in the side lanes with an initiator mid(like batrider) and a support helping a carry top or bot. There is also the trilane setup (1-1-3) where a hero who can handle 1v2 situations is sent to the offlane while a carry and 2 supports(usually with an initiator) are sent to the safe lane. While the carry kills the creeps in the lane for gold, one of the supports harass the enemy heroes while the other hero pulls their creep wave every 30-60 seconds using the creep camp closest to the lane. For heroes to start off with based on their primary attributes, I recommend sniper for agility (carry, similar to marksman in LoL), wraith king for strength (carry, has one targeted stun and 3 passives), and finally Warlock for intelligence (support, has an ultimate similar to Annie's Tibbers but always stuns with a large AoE). I hope this helps.