In aspx files you can use several different tags for embedded code blocks, also called inline code blocks. If you tend to forget what they all mean, here is a short explanation with further links. And here is a longer explanation from MS.
To set a Text of a Label to a resource called Pres in the App_LocalResources for your current page, you shall use this syntax: Text="<%$ Resources: Pres %>"
. Spaces are optional.
Similarly, to access a resource called Volume in the App_GlobalResources folder in a file called Msg.resx you shall use this syntax: Text="<%$ Resources: Msg, Volume %>"
. Spaces are optional.