When you are mapping to the HubSpot Deal Stage from your CRM systems Opportunity object, you will need to add in your CRM Stages so that they align. This is no different then how you ensure two select-type fields are aligned with the options that are available.
How you edit and add values to your Deal Stages in HubSpot can be a little tricky so here are some things to be aware of.
Editing Deal Stages
Unlike other field properties in HubSpot, you manage your Deal Stages in a specific location in their CRM. Check out this help article on how to manage your Deal Stages so that they align with your CRM stages.
When you are adding in your Stages to match your CRM Opportunity Stages, make sure to create brand new Stages and avoid editing the pre-existing options that HubSpot provides out of the box. We have noticed that by doing this there can be some confusion with matching the values due to how HubSpot handles the internal value structure of Deal Stage.
Pipelines in HubSpot
There is a field called the Pipeline that we require to map in order to see Deals in HubSpot. They allow you to create multiple Pipelines as a HubSpot CRM user, however, this is not recommended for the Formstack Sync integration as this can lead to confusion in the sync when trying to map your Stages since the Pipeline field and Deal Stages are dependent fields.