If you want to start learning and reading about triathlon, below are some useful links to get you started.
I have grouped them under some general headings.
1. Race Day
https://www.trainingpeaks.com/blog/build-your-ability-to-dig-deep-in-competition/
2. Strength, weights and plyometrics
https://www.active.com/triathlon/articles/mark-allen-s-12-best-strength-exercises
https://www.trilifecoaching.com.au/20-minute-whole-body-kettlebell-workout/
https://www.trainingpeaks.com/blog/strength-and-power-training-for-triathletes/
https://www.trainingpeaks.com/blog/should-endurance-athletes-do-plyometric-training/
These 4 Static Strength Exercises Will Make You a Better Athlete
Ask a Trainer: What Are the Best Plyometric Exercises for Triathletes?
The One Glutes Exercise You Should Be Doing But Probably Aren’t
https://greatist.com/fitness/kettlebell-workouts-for-shoulders#1
https://greatist.com/fitness/kettlebell-workouts-30-minute-total-body-routine#2
3. Swimming
https://www.active.com/triathlon/articles/2-swim-sets-to-help-increase-your-speed-in-the-water
https://www.trainingpeaks.com/blog/swimming-technique-for-triathletes/
4. Nutrition
Why the People of Okinawa Japan love Turmeric Tea
https://www.trainingpeaks.com/blog/the-importance-of-carbohydrates-and-glycogen-for-athletes/
Recommended Reading
https://www.33fuel.com/blogs/default-blog/news-inflammation-and-food/
https://www.trainingpeaks.com/blog/your-14-step-guide-to-weight-loss-during-base-training/
https://www.trainingpeaks.com/blog/rethinking-the-60-percent-rule/
https://www.trainingpeaks.com/blog/energy-partitioning/
5. Fat adaptation
How To Tap Into Fat For Fuel
6. Tapering
Coaching: How to taper and why it’s the best (legal) performance enhancer
https://www.trainingpeaks.com/blog/dave-scotts-perfect-ironman-world-championship-taper/
7. Training Plan links (not mine)
https://www.active.com/triathlon/articles/your-6-month-ironman-training-plan
Super Simple Ironman 70.3 Triathlon Training Plan
Free 12-month Ironman training plan
https://www.trainingpeaks.com/blog/what-is-training-periodization/
8. IronMan Official Website
https://www.ironman.com/finish-line-cameras
9. The Mental Game
https://www.trainingpeaks.com/blog/how-to-recalibrate-your-motivation-for-2020/
https://www.trainingpeaks.com/blog/daily-habits-for-high-performance/
https://www.redbull.com/gb-en/breathing-techniques-for-sport
https://www.verywellfit.com/breathing-exercises-for-athletes-3120044
https://www.trainingpeaks.com/blog/developing-mental-toughness-are-you-tough-enough/
10. Units and Tri time calculator
https://www.unitjuggler.com/convert-speed-from-kmh-to-minkm.html
https://totaltriathlon.com/triathlon-training-tools
11. Sleep and tracking fatigue
A Triathlete’s Guide To Better Sleep
https://www.trainingpeaks.com/blog/the-metrics-athletes-should-track-every-morning/
https://www.trainingpeaks.com/blog/5-considerations-for-quantifying-stress/
https://www.trainingpeaks.com/blog/pulse-oximeter-altitude-training/
12. Running
https://www.runnersworld.com/advanced/a20807282/threshold-training/
https://www.active.com/running/articles/the-benefits-of-running-slow
13. Power Meters
https://www.trainingpeaks.com/blog/how-to-get-started-training-with-power/
14. Cycling
https://www.trainingpeaks.com/blog/choosing-the-right-indoor-cycling-app/
https://www.trainingpeaks.com/blog/three-ways-to-improve-functional-threshold-power/
https://www.trainingpeaks.com/blog/youre-training-too-hard-for-criteriums-heres-why/
https://www.trainingpeaks.com/blog/4-key-workouts-for-criterium-training/
Coaching: Sweet Spot Training
VO2 Max Workouts
Top 10 Free and Paid Indoor Cycling Apps for 2019
Recruit your glutes: how to make the most of the biggest muscle in your body
15. Injury recovery
https://www.trainingpeaks.com/blog/recovering-from-a-broken-collarbone-part-1/
https://www.trainingpeaks.com/blog/got-plantar-fasciitis-do-these-5-mobility-exercises/
16. TrainingPeaks
https://www.trainingpeaks.com/blog/applying-the-numbers-part-2-training-stress-score/
https://www.trainingpeaks.com/blog/applying-the-numbers-part-1-chronic-training-load/
https://help.trainingpeaks.com/hc/en-us/articles/204071934
17. Supplements etc
https://www.saltlaboratory.com/pages/buy-magnesium-oil-spray
Creatine supplementation: what all athletes need to know