4 × 8:00 at threshold, 3:00 easy between. Type it in and the slip keeps your time, TSS and zone mix, then take it to the road or the trainer as a Garmin workout. No login, no plan to follow.
Blocks are reps × duration @ %FTP, with an easy spin between reps. Set your FTP and the stress score is live.
Four sessions to begin from. Tap one and it drops into the builder, then change whatever you like.
Percent of FTP, the standard model. If you don't know your FTP, a hard-but-steady 20-minute effort × 0.95 is close enough to start.