Complex sentence: Ewert Sundja, Erki Pärnoja and Kristjan Kallas are friends who first started playing together in 2008 for couple of concerts where they mostly played covers of Sting, Radiohead, Jeff Buckley and others.
Split into simpler sentences: Ewert Sundja, Erki Pärnoja and Kristjan Kallas are friends who first started playing together in 2008. For the first concerts, they mostly played covers of Sting, Radiohead, Jeff Buckley and others.