To assign a page to be accessible by everyone, with a password or only a members group, you can do that by clicking on Pages or a folder where your page is located. Find the page you want to restrict access to and click on the Three Dots Icon to get to the page settings.

For example, if you want to set the page only for members, in the Page Access drop down select Members Only and click on Choose Member Groups, after that all you need to do is select what groups should have access to that page. This also applies to funnel steps.

You can have the page: