Welcome to the Bunnings Workshop community @hextor. It's great to have you join us and many thanks for your question.
You would need to check your local states requirements but for example, according to NSW Fair Trading, to get a licence or certificate to do waterproofing, you need one of the qualifications listed below:
CPC31411/ CPC31408 Certificate III in Construction Waterproofing or
BCG31403 Certificate III in Waterproofing (General Construction) or
Qualification 90464 Certificate III in General Construction (Waterproofing) TAFE course #8126.
To find organisations that offer nationally recognised training, go to training.gov.au and search by the course code or name.
We wish you all the best in your waterproofing course and look forward to you sharing the projects in which you apply it to.
Please let me know if you require further information or have any questions.