Hello,
I.MX8MP is not supported on MCUXpresso IDE, you need to compile the code using GCC or IAR.
Once you downloaded the SDK from MCUXpresso SDK builder, you need to compile it using IAR or GCC to generate the files that needs to be uploaded to the board.
One alternative that could be helpful is MCUXpresso for VS Code that supports SDKs for i.MX.
For more information, please check next link.
Best regards.