make the menu bar from black to red, any advice?

They would have recommended the Firefox plugin as it allows you to see which css rules are applied to different elements that make up your web page.

For example, I just used Google Chromes Developer Tools to see where the rule was that was making your menu bar black.

From this you are then able to change it and see what it will look like.

If you are planning on making a lot of CSS changes then using a child theme is highly advisable.