In Salesforce Marketing console, click you’re name(top right)->Setup
Click Apps->Installed Packages
Click New and choose a Name - e.g. “Reco S2S”
On the new package page choose Add component
Click Save
Copy the following:
Client Id
Client Secret
Server URL
Copy the server URL from the Authentication Base URI, e.g. if the URI is https://mcrs7--r26k-skb3rhq.auth.marketingcloudapis.com/ the server URL will be mcrs7--r26k-skb3rhq.
Account ID
Click on the Organization name on the top right
The Account ID is the MID number - e.g. 536226888
Enter the copied values to Salesforce Marketing integration page