The first statement is completely true, and the second could be true depending on what the authors of the article meant by 'invoked'.
As can be found on the U.S. Department of Defense press release page, the DOD's first use of the Defense Production Act occurred on April 10th, and is what was meant by "It is the Pentagon’s first project under the DPA in response to the pandemic":
First DOD Defense Production Act Title 3 COVID-19 Project
APRIL 11, 2020
Statement attributed to Lt. Col. Mike Andrews, Department of Defense spokesman:
First DoD Defense Production Act Title 3 COVID-19 project:
$133 million investment will increase U.S. domestic N95 mask production by over 39 million over the next 90 days
"On the evening of April 10, the Department of Defense received approval from the White House Task Force to execute the first DPA Title 3 project responding to COVID-19.
As for the second statement, in the most literal sense the DPA was first used by the U.S. Department of Health and Human Services on April 8th, which was a contract with General Motors to produce ventilators:
This week, the Department of Health and Human Services announced the first contract for ventilator production rated under the Defense Production Act, to General Motors. GM’s contract, at a total contract price of $489.4 million, is for 30,000 ventilators to be delivered to the Strategic National Stockpile by the end of August 2020, with a production schedule allowing for the delivery of 6,132 ventilators by June 1, 2020. The rating of this contract under the DPA follows President Trump’s direction to HHS Secretary Alex Azar to invoke the Defense Production Act with regard to GM’s production of ventilators on March 27.
This invocation would only have been a few days before the Department of Defense's use of the DPA, so saying "Trump has invoked it several times in recent weeks" isn't true if the authors of the article are saying "invoked" to mean actually using the DPA to force companies to prioritize their contracts.
However, and this is getting into semantics but I want to cover all possibilities, the authors of the article could have meant "invoked" as just "appealed to", i.e. threatening to use the DPA to convince companies to prioritize contracts for critical supplies without actually using the provisions of the act to require them to. Trump has repeatedly talked about using the DPA since signing an executive order on March 18th which gave Alex Azar, his Secretary of Health and Human Services, the ability to use the DPA to place orders for critical medical resources. In this case, the second statement would be true, though as I said this is just up to interpretation of the author's wording so it's hard to say for sure if this is what they meant.