There's total chaos around the White House, as no one is quite sure what Trump is going to do about his massive new tariffs

Win McNamee

• President Donald Trump is set to make an announcement about new tariffs on Thursday.
• But no one, even in the White House, seems to know exactly what the announcement will be.
• The confusion is indicative of a volatile rollout of the massive trade policy.

President Donald Trump is scheduled to sign an order to impose new tariffs on imports of steel and aluminum at 3:30 p.m. ET on Thursday.

The only problem: No one seems to know what he is signing.

The details around the new tariffs, which function as taxes on imports of the metals, have so far been sparse. It's unclear if the order Trump will sign on Thursday will be a precise legal language or merely a symbolic step.

NBC News' Kristen Welker reported Thursday morning that the exact details of the tariffs are still being worked out and the signing on Thursday could be "symbolic."

Trump offered little specifics while teasing the event on Twitter.

"Looking forward to 3:30 P.M. meeting today at the White House," the president said. "We have to protect & build our Steel and Aluminum Industries while at the same time showing great flexibility and cooperation toward those that are real friends and treat us fairly on both trade and the military."

The Washington Post's Josh Dawsey also tweeted "no one knows" what the announcement will be.

The chaos over the announcement appears to be indicative of a rollout that has been rife with discord and confusion.

Before Trump initially announced he would impose the tariffs last week, White House officials told reporters that a White House meeting with steel and aluminum executives was simply a "listening session." Then, midway through talking to reporters, Trump announced the tariffs after all - a 25% tax on steel and 10% on aluminum.

That was only the start of a week filled with uncertainty.

The president's own party was taken off guard. Republicans in Congress said they were blindsided by the move and have been scrambling ever seen to urge Trump to reverse course.

A meeting with business executives who would be harmed by the tariffs was in the works for Thursday, and then canceled. Gary Cohn, Trump's top economic adviser, announced his resignation on Tuesday in part due to his ideological split from Trump on tariffs.

Even the policy itself has changed wildly depending on the day.

As late as Wednesday, White House press secretary Sarah Huckabee Sanders said that the tariffs will likely include exemptions for Canada and Mexico for "national security reasons." Sanders said other countries could see similar exemptions.

That represented a significant shift from White House officials' initial rhetoric. As recently as Sunday, top trade adviser Peter Navarro said on CNN that "at this point in time, there will be no country exclusions."

Canada and other allies were threatening to respond to Trump's move with trade restrictions of their own.

According to Politico's Andrew Restuccia, what exactly those exemption will look like is still up in the air. Among the possibilities being considered is a quota, or set limit on the amount of imports, for Canada and Mexico.