Your business has begun using Salesforce Lightning and you are wondering if there are specific steps or extra requirements for enabling MSI within Lightning.
Marketo Sales Insight will automatically work within Lightning without additional install steps.
You will find MSI within the Record Details on Leads, Contacts and Accounts.
If you are trying to edit a visualforce page to place MSI on another page layout other than Details, you will not have success. MSI is not customizable. It will only appear in the Details section within Lightning.