A Sharepoint Admin, who is ALSO set up as an Admin on HowNow will need to take the following action.
As an Admin, head to the Dashboard and select Apps. Then search for Sharepoint and toggle it on.
Click on your profile picture and select My Profile. From here, click the Integrations tab and click Connect next to the Sharepoint option.
As the account owner for your organisation's Sharepoint, you need to approve access to the account, by ticking the Consent on behalf of your organisation checkbox.
Once this is done, your Users will then be able to authenticate their own Sharepoint credentials to gain access to the content they need.