Head over to Linkedin developers(opens in a new tab) and create a new app.
Fill in all the details, once created head over to Products and make sure you add all the required products.
It is important to request the Advertising API permissions and fill up the request form, or you will not have the ability to refresh your tokens.
Make sure your redirect URL is set to http://localhost:4200/integrations/social/linkedin for local development. Copy the created Client ID and Client Secret and add them to your .env file.
LINKEDIN_CLIENT_ID=""
LINKEDIN_CLIENT_SECRET=""