Setup versus ongoing usage
Your product is likely to have two very different classes of user stories: those associated with setting the product up and those with its ongoing usage. In terms of total use, the ongoing cases vastly outnumber the setup ones – that is, unless you’re experiencing massive customer growth and turnover simultaneously.
Despite being the minority of interactions with your product, getting users onboarded takes a disproportionate amount of design time relative to other features. When first using your product, users will know the least but also have some of the most challenging tasks to perform around getting your product ready. Unless they can overcome that barrier, they’ll never become regular users.
You should devote similar proportions of time to testing onboarding tasks as setup tasks. On the plus side, this form of testing needs very little test data or equipment. The whole point is that you are a new user with no prior history...