https://sabbia.westus2.cloudapp.azure.com/iis-sandbox/fhir/tenantId/
You will need to place the IIS Sandbox Facility Id where the tenantId is indicated.
The IIS Sandbox supports multitenancy for FHIR. Which means that resources submitted to the sandbox will be placed in dedicated buckets of data that are separated from data by different tenants (facilities.) This is different than IIS which will merge data from all submitters. The IIS Sandbox keeps submitted data separate to support testing from multiple agencies.
IIS Sandbox v0.5.8 - AIRA Privacy Policy - AIRA Terms and Conditions of Use