Install:
1. Log into your account at: https://app.nativemsg.com/#/auth/login
2. Navigate to Settings > Integrations (located at the top of the page)
3. Locate the HubSpot card and select manage
4. Click Install
5. Select your HubSpot account (portal)
6. Click Choose Account
7. Review the requested scopes on this screen. nativeMsg RCS Messaging requests access to read and write to contacts and companies and read and edit contact and company properties
8. Click Connect app
9. You will be redirected to the nativeMsg "Integrations" page and new configuration options will appear. See the next section
Configure:
In your In your HubSpot account, go to > Settings > Integrations >Marketing Contacts where you will see a Turn on to sunc contacts as marketing contacts switch.
1. Toggle "Sync" to initiate One-way nativeMsg RCS Messaging marketing contacts sync and HubSpot will only update the nativeMsg with the results of your the workflows you create with the nativeMsg RCS Messaging app. A confirmation message will appear. 
2. Mapping is not required and only the data required to initiate workflow activities (SMS, MMS, RCS messages) is sent to the nativeMsg application to initiate message sending (ex. phone number).
3. When ready, toggle "Sync" from "OFF" to ON
5. Click Done
Use:
nativeMsg RCS Messaging automatically keeps your nativeMsg messages synced with your HubSpot contacts and companies according to your configured settings (see "Configure" section above). Syncs run at least every 5 minutes. No manual actions are required.
Disconnect:
Note: If you disconnect your HubSpot account from nativeMsg RCS Messaging, nativeMsg lead and account data will no longer sync to HubSpot contacts and companies (and vice versa). Existing data will remain on your HubSpot records.
1. Log into your nativeMsg account
2. Navigate to Settings > Integrations
3. Locate the HubSpot application integration
4. Click Manage, select Remove from any connections you have created.
5. You will be asked if you are sure, click Confirm.
Uninstall:
To uninstall nativeMsg RCS Messaging from your HubSpot account, follow the instructions in this HubSpot Knowledge Base article.