I would suggest Upwork or Guru for smaller projects, especially around training.
Just make sure that you look at the material from the trainers and get a good feel for what they do and how they do it. I would also encourage staying within your time zone, that will also likely provide talent that has better English and can work on your schedule.
Ask potential freelancers to provide a short video or audio with a 30 second training. This will show you the way they teach and their style. This should help you make a better decision to find the right partner.