Once you receive the invite from vmware then you setup your org, create a myvmware account (or linked the existing one) after that you can invite other users and make them org user or org admin (The only difference is org admin can invite other users)
Once this is done you create a subscription for you based on your requirement for number of host (The number of host cannot be more than the maximum allowed for your organization)
Steps to create a subscription
1 - Log in to the VMC Console at https://vmc.vmware.com.
2 - Click Subscriptions.
3 - Click Create Subscription.
4 - Select the number of hosts you want as part of the subscription.
The total number of subscribed hosts cannot be more than the maximum allowed for your organization.
5 - Select the region for these hosts and click Next Step.
6 - Select a subscription period and click Next Step.
The VMC Console shows the cost to and the discount compared to on-demand pricing for each subscription period.
7 - Review the summary and click Place Order.
Once this is done you will receive an e-mail notification indicating that your subscription order is received and once the order is processed the next email will come in as if the subscription is successful or failed.