Trials of Serenity tutorial videos.
This one was tough for me and I couldn’t be the third level with by 4-star classic hero bench. The first two levels are fairly reasonable for a 4-star bench. The third level however is very difficult without a healer. The only healers qualified for these quests are Ares, Aegir and Red Hood. I tried using my mono-purple ranger/paladin team and ran out of healing pots. Ultimately I had to use Lianna, Triton, Aegir, Athena and Buddy.
Levels 1 and 2 completed. Failed Level 3.
Level 3 - Challenging. The link below jumps straight to the beginning of my successful run using 5-star heroes.