Complex sentence: Chandler was a key figure in Hendrix's rise to strong critical and commercial success, including providing somewhere for him to stay, and for self-financing the Experience's first single, "Hey Joe", before they had a recording contract.
Split into simpler sentences: Chandler was a key figure in Hendrix's rise to strong critical and commercial success. As part of his associatiuo with Hendrix, he provided somewhere for him to stay and financed the The Jimi Hendrix Experience's first single "Hey Joe", before they had a recording contract.