Limited membership advice/plugin needed

I’m a fairly new WP user and need to set up members-only access for a

small portion

of my hobby club’s website. That section is only for people who are already members of the club. The public will not be able to become members on line but will be able to see the rest of the site. I’ve installed the s2member plugin but it’s overwhelming and I don’t have a clue how to apply it to my limited needs.

I know I’ll need a login page, but I think I’ll want to enter the members login names and assigned passwords from the back end so that members of the pubic will not be able to enter their own. Has anyone set up a similar situation? Thanks in advance.