You would place the attribute in the opening tag only. For example, if we wanted to modify a paragraph tag it would look like:
ID attributes cannot have spaces in between words, so either you use a hyphen or keep the words together. I personally like to use a hyphen.
In CSS, you would create a rule and for IDs you need to use a hashtag (#). So:
You always have to use a hashtag and curly brackets to enclose your commands. So for this CSS rule, I want my specific paragraph to be green. You also have to ensure you use a colon after the property and a semi-colon after the value. Please note that IDs are case sensitive and need to be lower case only. Also, when you are typing in CSS, the ID does not need to be in the brackets.