Hi Mark Berry,
Thank you for reaching out to us on the Microsoft Q&A forum.
It looks like you’re on the right track but having trouble finding the “Define your workloads” section in the TCO Calculator. Follow the steps outlined in the module to successfully complete the creation process.
By clicking on the TCO Calculator, you'll be directed to the new page, please check the screenshot for reference
As shown in the figure above, locate the "Define your workloads" section. Then, select "Add server workload" to create a row for your Windows Server VMs.
Then, enter the values for each field as specified in the module.
If you experience any other problems, please inform us in the comments, and we’ll be more than happy to help. If you found the answer helpful, please show your appreciation by clicking "upvote" or "accept answer”.