Here is the timeline - https://www.nytimes.com/article/trump-classified-documents-investigation-timeline.html (web archive of the link - https://archive.ph/Jzpn1)
THIS is how federal government agencies operate - they go through their OWN processes and procedures to resolve the problem FIRST and when they run into problems, they will refer to DOJ to use the courts to compel compliance. THAT is what NARA did -
Late 2020
Talks begin between the National Archives and Trump.
The Trump White House begins having conversations about transferring presidential records to the National Archives, as required by the Presidential Records Act.
(snip)
Jan. 18, 2021
The move to Mar-a-Lago begins.
Two days before Mr. Trump is to leave office, at least two moving trucks are spotted at Mar-a-Lago, his club and residence in Palm Beach, Fla.
(snip)
May 6, 2021
The archives alerts Trumps team to missing material.
Gary M. Stern, the archives general counsel, emails Mr. Trumps representatives the lawyers Patrick F. Philbin, Michael Purpura and Scott Gast saying that the government had discovered that the original correspondence with Kim Jong-un, the North Korean leader, was missing, as was a letter that President Barack Obama had left for Mr. Trump at the White House upon leaving office.
(snip)
Late 2021
Archives officials warn of consequences.
Officials at the archives warn Mr. Trumps representatives that there could be a referral to the Justice Department or an alert to Congress if the former president continues to refuse to comply with the Presidential Records Act.
(snip)
Feb. 9, 2022
The archives refers the matter to the Justice Department.
The archives tells the Justice Department that a preliminary review of the 15 boxes recovered in January indicated that they contained a lot of classified records, including highly classified records that were unfoldered, intermixed with other records and otherwise unproperly identified.
The next day, the House Oversight Committee announces an investigation into the records retrieved from Mar-a-Lago.
Spring 2022
Investigations into the missing material ramp up.
A grand jury is seated to look into the missing boxes of documents. The F.B.I. begins interviewing several of Mr. Trumps personal aides as well as three former White House lawyers who had been among Mr. Trumps representatives to the archives.