To check inbound form leads on Squarespace, you'll need to follow these steps:

Log in to your Squarespace account.

Click on the "Home" button on the left-hand sidebar of the dashboard.

Scroll to the "Activity" section and click "Form & Button Conversions."

You will be taken to a page that shows a list of all the forms and buttons on your site that have received conversions.

Click on the name of the form that you want to view the leads for.

You will be taken to a page showing a list of all the submitted leads through that form.

Click on the lead's name for more details about a specific lead.

You can export the lead list to a CSV file by clicking on the "Export" button at the top right corner of the page.

It's worth mentioning that Squarespace also allows you to set up email notifications for form submissions, so you can receive an email each time someone fills out a form on your site. You can enable this feature by selecting the form's settings and selecting the "Email" tab.