Take a 10–20 minute taxi from Riad Bab 54 to Jardin Majorelle to beat later crowds; taxis are inexpensive and faster than walking for this northbound trip. (Jardin Majorelle typically opens around 8:00–9:00 — verify current hours before you go.)
Explore the iconic cactus and palm garden and the Yves Saint Laurent museum if you want; the gardens are a calm, colorful oasis and great for photos and plant lovers. (Typical opening ~8:00–17:30/18:00 — confirm exact hours and book tickets online if possible.)
Enjoy an early, well-reviewed and reasonably priced lunch at Café des Épices in the medina near the spice square; popular for fresh, simple Moroccan and Mediterranean dishes and a good spot to rest between sights. (Open from the morning; plan 1–1.5 hours for food and a short break.)
Visit the historic Ben Youssef Madrasa to admire the intricate woodwork, tilework and courtyard — a must-see example of Moroccan Islamic architecture in the heart of the medina. (Usually open ~9:00–17:00; check current hours and allow 30–60 minutes.)
Allow time to return to your spa location and check in for your reservation; plan a 15–30 minute transit depending on traffic and whether you walk or take a taxi. (You have a 14:30 reservation — arrive ~10–15 minutes early to check in.)
Enjoy your pre-booked hammam/massage or chosen spa treatment at Les Bains Marrakech; this is a relaxing, pampering break and perfect mid-afternoon. (Spa hours vary; your reservation time is confirmed so arrive slightly early.)
After the spa, stroll through Jemaa el-Fna and the adjoining souks to soak up the atmosphere, shop for small souvenirs, and watch street performers as daylight wanes. (Open-air area — free to explore; shops vary in hours but many stay open through evening.)
Head back to Riad Bab 54 to freshen up and get ready for dinner; allow 20–30 minutes travel and 30–45 minutes to rest and change. (No breakfast included per your note.)
Dine at Naranj (Lebanese/Middle Eastern) — a highly rated spot with flavorful sharing plates and good atmosphere; your 19:00 reservation ensures a relaxed evening meal. (Reservations recommended; open through the evening.)