I am pretty new to CSS. My band's website was built using a template offered from another site. I can override the CSS with a special editor they offer. One thing I am trying to do is make an object more transparent so the background photo comes through more. I know this is done with the 'opacity' property, but I'm unsure what the coding should actually look like. I'm also interested in controlling the dimensions and placement of these object. It's a rectangle that appears on several of my pages.
Here is an example of a page that has this rectangle: