Can I use resource links next year?

I've been putting either Dropbox files or links into lesson plans for the last few weeks.
Now comes the question - was it just for those lessons which have now taken place or can I somehow use the lesson plan with next year's classes and re-use those links or files.?

You can use that lesson plan for years to come.

Open a particular class, tap on its diary -any of the red ribbons below- and now tap on Tools (top bar) > Copy annotations.
You will be able to select the dates to copy from and to and the target class