Complex sentence: His first band was "Eurika" and this was the band with which he got his first gig, in 10th grade for a fund raising concert for "Blind School", Kalimpong.
Split into simpler sentences: His first band is "Eurika" and this was the band with which he played his first ever gig. This was while he was in 10th grade for a fundraising concert for "Blind School", Kalimpong.