Note: Similar to all other all information on this wiki, inclusion of a practitioner here should in absolutely no way be treated as a recommendation. This is simply a starting point for research.
It is extremely difficult, arguably impossible, to implement a Walsh style protocol without proper help. Partly this is because there are many, many variables involved but also because a practitioner can get you access to testing (and, critically, interpretation of those test results) which allow you to know exactly what it is you need to change.
Bear in mind that if you decide to try supplementation without a practitioner and see an improvement, you will not know if you could improve far further with more help. Or, very importantly, whether you should now reduce how much you are taking of a particular supplement since you may have now improved your status for that particular substance. Continuing to take large doses of supplements when they are no longer required can be very damaging.
Seeing a practitioner may not seem cheap but the cost must be considered against the huge, huge value it can bring to your long term health.
Many practitioners offer consultation using phone or Skype but of those, many will insist on at least one in-person consultation.
This is often necessary simply because it's not possible to get blood testing arranged outside of the clinic, and blood testing is very important.
Note that if you live a long way from a major city it may not be possible to get samples overnighted. That is often required for things like stool and urine tests which can otherwise be taken at home. Check with your practitioner since it can make sense to have the sample kits sent to you, and then bring the (recently taken!) samples to the consultation so they can be overnighted from there.
Of course, all these details vary with both your own and your practitioner's circumstances so they are best discussed when you are looking for someone to work with you.
Worldwide:
https://www.walshinstitute.org/clinical-resources.html
Australia:
https://www.biobalance.org.au/find-a-bio-balance-trained-doctor/