I know countables can be used with ordinal numbers. We can say "the second book," etc. But what about uncountables like "information"?
I'd appreciate your help.
There's nothing special about singular and plural used with ordinal numbers.
If you had three piles of books and you were telling people to take the second book from each pile, you might say remove the second books, but there's nothing special about this usage. When referring to a single pile, you would say remove the second book.
Information by itself as a noun usually refers to something abstract and non-tangible, so you can't make it plural. To make it specific and tangible, you must qualify it. When you qualify it, the qualifier becomes the noun and information becomes an adjective. If there is more than one, you make the noun (qualifier) plural.
For example, if you told someone:
refer to the information provided
information refers to something abstract, so you can't make it plural. It could be an unknown quantity of data or it might not even be the same for everyone, depending on what was provided to different people.
To make it specific and tangible, you need to qualify it, for example:
refer to the information sheet provided.
If there is more than one sheet, you would say,:
refer to the information sheets provided.
If you want the person to look at the second sheet, you would say
refer to the second information sheet provided
Whether you use ordinal numbers has no bearing on the result.