Complex sentence: The campaign works with the Calling All Crows non-profit to organize tour projects and over the last year it has worked with more than 600 fan volunteers working nearly 4,000 hours to improve schools in North America and Europe.
Split into simpler sentences: The campaign works with the Calling All Crows non-profit to organize tour projects. It has worked with more than 600 fan volunteers working nearly 4,000 hours to improve schools in North America and Europe.