I'll give it a whirl and if you have follow up questions don't hesitate to ask though it'll take some time to respond later. I'll assume this is predicated in three parts.

1. What was Hitler's ultimate goal in Europe and for the world at large.
2. Did he think he could win even though his forces would be spread thinly fighting France, England, and Russia, possibly (later) the U.S. as well.
3. Why invade Russia at all.

We'll work with the assumption that these are your 3 primary questions and proceed from here.

1. Hitler's ultimate end game is hard to puzzle out because he never achieved and it's hard to decide what he was being factual about and where he was either deceitful or delusional about his desires and ability to achieve them. His stated endgame probably would have looked like a very strong and unified German state that included a rash of new territory. France would have been thoroughly cowed and humiliated and Britain would have become a prominent ally of Germany in his fight against communism. His plans for the U.S. are slightly more murky and less defined although probably along a similar vein to his thoughts on Britain. Russia would have been the enemy of the world essentially and with the help of his new allies he would have crushed them. His plans for places like Africa or Asia are impossible to know or if he even cared at all about them so I'll leave that out, but ultimately his world would have looked much as it did with the Western allies siding with him instead of Russia.

2. He undoubtedly thought he could win, particularly at the start of the war, whether he could win or not is far more interesting. The truth is that long term without serious help from Britain or the U.S. it's unlikely he could have defeated the Russians in a lengthy war. Germany's ability to fight as long as it did is a testament to their skill and they were almost inevitably and inexorably, no matter how much blood they drew from the Russians, forced backwards from 1942 onwards.

3. So why Russia, well it's simple really, a clash between them was inevitable and Hitler believed that he could capitalize on his immense and oftentimes stunning successes to force the Russians into an early capitulation. He wasn't necessarily wrong either. The situation was only going to get worse after 1941, they couldn't match Russia's production capacity and they certainly couldn't match their manpower. Their army was battle hardened and tested, brimming with immense confidence and conviction against an inexperienced foe wracked with doubt, intrigue, turmoil, and fear. The German's devastating Operation Barbarossa succeeded beyond many German generals expectations and served to highlight the true state of the Russian armies which was utter and complete chaos and disarray. They would suffer 5 times as many total casualties, 20,000 airplanes, probably a similar amount of tanks and other tracked vehicles. The German victory was almost a complete success, but that almost part would become haunting and further offensives would never achieve that same level of success. Almost from Barbarossa forward the Russian army grew in experience becoming battle hardened, grisly, determined, brimming with an almost grim self assurance of the victory and death it would bring. By comparison the German army was slowly whittled away until they were an army wracked with doubt, intrigue, turmoil, and fear of the inevitable death and destruction coming for them.