Log in to your Salesforce Marketing Cloud account.
Go to Setup (upper right corner under your name).
Apps (on the left panel under Platform Tools)
Create a new package and make sure to give it all the permissions.
Under the package, add a component (use your account subdomain to enter the URI https://SUBDOMAIN.auth.marketingcloudapis.com/ and hit Save
The component gets added along with the Client ID and Client Secret
Now log in to your callhippo account and go to the integrations tab.
Click on +integrate button of Salesforce Marketing Cloud.
Now you will be redirected to another page. Click on +connect your Salesforce Marketing Cloud.
Now enter the details you noted in the above steps.
Now click on save. It should say Datasource is linked.
Click on okay. And click on next
You should now be redirected to callhippo account and your status would be changed to Integrated.