(sic)

ruzzian backed and organised separatists

You mean Ukrainians. The term is "Russian backed separatists."

It just means Eastern Ukrainians who oppose the new government formed in Western Ukraine. This made them "separatists." They declared their independence and formed their own self-proclaimed Donetsk People’s Republic (DNR) and Luhansk People’s Republic (LNR). They felt the violent overthrow resulting in the sacking of the old Ukrainian government was questionable due to close involvement by foreign countries, who deem it a "people's revolution." They also question the referendum election that followed, which was largely paid for, organized, and had their candidates vetted by, those same foreign countries.

They are in Eastern Ukraine, called the Donabass region, which is short for Donetsk Basin. This was historically industrial hub and revenue center of Ukraine, due to it's mining. It sits Yet, through WWII, being a key military pass from Europe to the East, occupation of various regions of Ukraine by Soviets and other countries has left little recent history that didn't involve struggle, turmoil, and ruin. Following the wind down of the war, mining boomed for a short time leading to an increase in Russian-Ukrainian population immigrants settling in the East.

Of course there is a West and East Ukraine and it is a starkly different one, with US and European backed parts like Kiev and Odessa in Western Ukraine. The Donabass region and Denetsk are parts of the Russian backed in Eastern Ukraine. Ukraine is split vertically, right down the middle, by the Dnipro River, making two distinct physical sides hard to deny.

Yet, mostly what divides them is them is their historic differing WWII occupiers, leaving them a country still at war with its self, East versus West. This wasn't helped by tensions created by, sometimes cruel, questionable, post war anti-communism overhauls.

The Eastern Ukrainians likely feel they've never not known war. The Donabass region was one of the bloodiest areas of WWII, then even before Ukraine's newly formed government in the East, they were bombing each other. The most casualties, post war, was in 2014/ 2015, it accounts for most of the UN's estimated nearly 60,000 deaths between the two sides of Ukrainian's civil war and at least 3,400 of them civilians, according to UN estimates.