I have been thinking bout this exact same thing for a week.
First, as most others, I would secretly kill off ISIS and any Mooslim radical I could get my hands on.
Then, I would create several hideaways - fortresses of solitude, in the most remote locations on earth. Just for me. I would also scour the earth for undiscovered antiquities - cause I like that sort of thing.
Super brain means super wealth. I would raid the stock market, bond market etc. Become the most wealthy man on the planet, by orders of magnitude. (my plan needs money). This includes all the gold, silver, diamonds I could find.
I would give everyone on the planet a year to relocate to their ethnic ancestral homelands. One year. North America with the exception of Mexico obviously belongs to Whites. So does South Africa.
I would then build literal walls with controlled ports of entry around every ethnically different geographic region, segregating humanity.
I would use the money to raise my own personal Army to police the walls and ports of entry.
Only two rules:
1. No intermixing, no diversity, no cultural contamination except through free trade. Literally ,ships with goods are all one will ever see of another race or culture.
2. Two nations or regions go to war, ever, over any thing, I kill everyone on both sides.
I will be the arbiter and judge, as will my offspring, to any disputes arising between nations. My decisions are final with no appeal.
Justice will be harsh.