Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
I think that, if it isn't in the manual, you need to just scan for channels, have the radio find them, and then see if the frequency you want is found and listed, and choose that frequency that way. It's how these radios work, by and large.
And to explain further: I suggest it be done that way, because tuning in to a frequency *isn't* some recondite arcane thing, nor some piece of "hidden knowledge," at all. So, if that isn't listed in the manual right up front (or obviously in the Table Of Contents of the manual) then it has to be done that way.