"America First refers to a foreign policy in the United States that generally emphasizes American nationalism, unilateralism, protectionism, and isolationism."
The US has 180 military bases around the world and isn't moving to close them by and large.
The US is the center of NATO and, despite Trump's occasional rhetoric, is not moving to leave the alliance.
The US is persistently using its naval projection capabilities to challenge China's territorial ambitions around Asia (including constantly sailing its navy through the illegally annexed South China Sea territory). Nobody else in the world can or will do that, including none of the fellow NATO members.
The US has a very large military presence in South Korea and Japan, positions both countries are openly thankful for and willing to pay more money to the US to keep (as North Korea continues threatening both countries and both are weary of China's military ambitions in the region). Currently the US has around 75,000 to 80,000 (!) military personnel stationed in South Korea and Japan combined.
The US is persistently deploying its military in the Middle East, including in Syria, Saudi Arabia and the waters near Iran.
The US is the extreme exact opposite of isolationist. Go by what the US does, not what Trump campaigns on to win an election (he also has built zero miles of a new wall on the Mexico border thus far and is deporting fewer illegal immigrants than Obama did, again despite his rhetoric to the contrary).
"America First refers to a foreign policy in the United States that generally emphasizes American nationalism, unilateralism, protectionism, and isolationism."