In Australia, the first place to go is the website to calculate how much can be originated.
Here is a short video on this.
For those who are inclined to read a bit more try the following
https://mootral.com/carbon-projects-carbon-credits/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8420989/
https://groundtruth.co.nz/wp-content/uploads/2022/05/InfoSheet_9v3b.pdf
https://www.publish.csiro.au/AN/pdf/AN15222
For those familiar with Accreditation by third parties such as Verra, here is their take on cattles.