You can connect your Salesforce to Instantly and import leads to your campaigns or lists. To achieve it, you must first connect your Salesforce account to Instantly.
Here are the following steps to connect your Salesforce:
Go to the Integrations tab.
Select Connect Salesforce.
Select the method to authenticate.
Click Continue to allow access to Instantly.
Log in to your Salesforce account.
Allow the access.
You will receive confirmation that the integration has been successfully connected.
Learn how to import the leads from Salesforce to campaigns and lists here.