Nothing should delete any part of a clip you're moving on the timeline. You can drag a starting or trailing edge of a clip to change the duration, but I'm having trouble understanding what you're describing.
Also. my first response was how to perfom the steps in PowerDirector as I didn't notice you'd posted in the AudioDirector forum. Please refer to the yellow horizontal line near the bottom of the clips for the main volume level.
If you're in AD's Mix room, all you should need to do is drag the audio on track 2 to match, like this:
If you still have trouble, can you please make a screen recording and upload it to YouTube then paste a link to it here so we can see what's happening? You can also use the Attachments button below the forum's text box to upload the recording here directly.