SUNNI + SHIA ARE TYPES OF MUSLIMS
SUNNI believe in following the Sunnah of the prophet Mohammed..
SHIA believe in the 12 Imams(pbuh)
The Sunni Shia split happened, over the succession after the death of Mohammed (pbuh) because Sunni believed it should be Abu Bakr, and Shia that it should be the prophet Mohammed's grandson Hussein..
And it has continued to this day (but whilst usually there is no fighting..this has been provoked by American divide plus conquer policies..
Most Shia live in Iran (and some in Afghanistan , Uzbekistan, UAE, Lebanon, and Albania, and parts of Iraq especially around Karbala etc which is a holy city and shrine of Imam Hussein)
KURDS ARE A NATION/ETHNIC GROUP..who live the area in Northern Iraq, Southern Turkey, Western Iran, and Eastern Syria..
They are not a religion..Most Kurds tend to be Muslim.(but not fanatical).
It is equally split between Shia and Sunni..There are of course even Christian Kurds..)
Kurds are the largest ethnic nation without a country and the most famous Kurd is perhaps Saladin..
Kurds call the area they live in Kurdistan
I am Kurdish