Notice that the tongue stays in place between the “t” and the “d”. You start to make the /t/ sound, but keep it in, and bring in the voice, letting go on /d/. Next, hear how “did” and “you” link with the /ʤ/ sound. The intonation starts with a fall, but rises, as it’s referring to something someone has already said, even though you didn’t understand clearly.
This phrase is very useful for a learner.