Original sentence: Some members of ELAS were Slavo-Macedonians from northern Greece, who established the National Liberation Front (NOF) in 1944, with the support of the Yugoslav leader Tito who had plans for Greek Macedonia.The civil war consisted on one side of  the armed forces of the conservative postwar Greek government, supported by the USA and the UK, and on  the other a large proportion of  Greek communists, and key members of the biggest Anti-Nazi resistance organization (ELAS), the leadership of which was controlled by the Communist Party of Greece (KKE)
Edited sentence: Many members of ELAS were Slavo-Macedonians from northern Greece, who established the National Liberation Front (NOF) in 1944, with the support of the Yugoslav leader Tito who had plans for Greek Macedonia.On the other side were mostly Greek communists, and key members of the biggest Anti-Nazi resistance organization (ELAS), the leadership of which was controlled by the Communist Party of Greece (KKE).The civil war consisted on one side of people from the predominantly conservative and centrist Greek civilian population  and the armed forces of the Greek government, supported by the USA and the UK