The drill file CycleMusicTimerDrills.cmt is a text file that can be edited with any text editor (like mac's TextEdit.app). It contains sequences of XML connecting your drills to the Artist Name + Track Name. Here are two examples, of many drills in the file -

        ...
	<key>Fifth Harmony|+|Sledgehammer</key>
	<array>
		<string>Fifth Harmony</string>
		<string>Sledgehammer</string>
		<string>Hill climb 
                  Hover/seated ham pull
                  16/18/20
                  Bpm =51</string>
		<string>Custom Cycle 53 - HIIT</string>
		<string>NO</string>
	</array>

	<key>Rick Derringer|+|Rock And Roll, Hoochie Koo</key>
	<array>
		<string>Rick Derringer</string>
		<string>Rock And Roll, Hoochie Koo</string>
		<string>Speed work 
                  Jumps
                  Bpm=100</string>
		<string>Custom Cycle 53 - HIIT</string>
		<string>NO</string>
	</array>
        ...

For each drill you see the key is formed by the Artist Name and Track Name. Then there is an array of strings containing the Artist Name, the Track Name, the Drill text (which can span multiple lines), the Playlist Name, and a flag to tell CMT whether the drill is unique to this playlist "YES" or "NO".

The Artist, Track, and Playlist names must match exactly with the names in the Apple Music app. If you manually edit this file be mindful of this.