Long run combined with tempo effort.
Wu: 20 minutes easy
Main: 7 x (3t, 2r) 3t efforts should be RPE 6-7. 2r at RPE 2.
Cd: 20 minutes easy
In the main set, the cryptic 3t and 2r means that there's 3 minutes at tempo or increased pace, followed by 2 minutes recovery running. So in total for the main set, you'll do 35 minutes total.
wu: 300 continuous- (alternate 25 swim, 25 kick)
main: 20 x 75 hold constant pace for each-so judge pace in the first few, RPE 5
cd: 200 easy