Hitler’s goals were to
1) unite all Germanic people,
2) acquire living space (Lebensraum) for them, and
3) rid the German area of ‘sub-human’ races to maintain Germanic racial purity.
He believed he could do this by pulling all people of German ancestry together under one leadership (which he mostly did); capturing lands to the east that were occupied by Slavs; and clearing those lands of undesirables, however defined.
He believed that if he could push Slavs out of all areas west of the Urals, permanently, there would be sufficient land for all Germans for the foreseeable future. If a growing population in the future requires more land, that could be addressed in the future. He had no plans for the conquest of the globe.
That said, he was not averse to having German colonies scattered around the globe, creating a presence to be exploited if that future demand developed. He was not interested in those colonies though — other than as German possessions — and didn’t make any efforts to expand them. He barely made efforts to defend them.
As far as the other ‘races’ went… well, Hitler and the Nazis were inconsistent and working from something akin to science, but not science.
They subscribed to a view about race that is considered archaic — at best — today. Strongly influenced by the growing science of linguistics (and perversions of Darwin’s theory of evolution), they felt that the Aryan was the pinnacle of mankind and civilization. Beneath that were other Europeans like Italians, French, Spanish, and Greeks. Lower still, but still within the greater Aryan fold, were Iranians and Indians, all of whom spoke Indo-European (or, as they were then called, Aryan) languages. Non-Aryan ‘races’ — Hungarians, Turks — were lower down the ladder.
African Blacks were the utter nadir, but there were very few Blacks among the Germanic populations at the time. During WWII, French colonial troops, who were Black, were often summarily executed when captured. Germany undertook the first modern genocide in dealing with the Herero people in SW Africa at the turn of the 20th C., though this was in the pre-Nazi era, of course.
Hitler had particular animus toward Slavs, even though they, too, spoke Aryan languages. Perversely, the Nazis would often ‘rescue’ Slavic children who looked ‘Nordic’ and ship them off to German to be raised in foster, German homes.
Among the worst crimes/sins for the Nazis was the willful mixing of the races. Germans who had married or even had affairs with people of inferior races were sometimes treated as though they were members of those races.
Arabs were seen as highly dubious; their language, after all, was Semitic. This did not prevent him from using them politically, of course, because they weren’t in any land he was particularly interested in at the time. They might become a problem in the future because they were sitting on oil, but through WWII, they could be allied.
Nazi racial theories about Asians were never really clear. While there was the admiration of the Japanese (and Koreans) as a ‘master race’, the Chinese were considered Untermenschen. I don’t think theorizing reached as far as considering, say, the Thais or Vietnamese. As they were so distant from Germany, the Nazis generally left their fate to the racism of Japan.
There are hundreds of books and scholarly articles written about Nazi racial theory. I’d suggest starting at Wikipedia and following the references to get a start at delving into them.