When you burn an Audio (Redbook) CD, the tracks are played back in the order they are placed on the disc. Track numbers are meaningless here.
When you burn a Data CD, then the files you burn to the disc are just data files, and the playback system will decide the order of playback. These files often would include track numbers to help the user or player to determine a playback order.
The numbers you see in MC's Burn disc area are the Sequence number and other metadata such as Track #, Artist, Album, etc. When you add the tracks, be sure they are added in the sequence order you want them to play back. Then, examine the Seq(uence) column to see if they are in the correct order. I don't see a way to re-order this burn list, so you'll have to get them order by the way you add them.