Ukrainian presidential candidate Yulia Tymoshenko is welcomed by his supporters during a rally in Priluki, Ukraine, Thursday, May 22, 2014.

Ukrainian presidential candidate Yulia Tymoshenko is welcomed by his supporters during a rally in Priluki, Ukraine, Thursday, May 22, 2014. Efrem Lukatsky/AP

Here’s Your Primer For The Ukrainian Presidential Election

Nearly two dozen candidates will attempt to unite Ukraine as Russia continues to drag its feet along the eastern border. By Marina Koren

It has been a long five months in Ukraine, and you've probably heard a lot about it. Its president was ousted after violent street protests, Russia took over an entire chunk of its territory, and separatist groups have wreaked havoc in its cities to the east.

On Sunday, all of this instability will serve as the backdrop for something that requires maximum cooperation: a massive, presidential election.

About 36 million Ukrainians are eligible to vote in the presidential election, which was scheduled to take place on March 29 before the uprising that drove Ukrainian President Viktor Yanukovych out and established an interim government in February. The winner will serve a five-year term—and help decide the future of the fractured country.

Here are the basics you need to know for Sunday's watershed event.

Weeks of presidential debates wrapped up Friday.

There are 23 candidates in total, 21 of whom agreed to participate in a series of televised debates this month. One candidate, whose campaign is financed by the richest man in Ukraine, has had his assets frozen by Switzerland over his role in the Ukraine crisis. Many are running as independents, including one who recently sat down with National Journal. You can read that interview here.

A poll of 6,200 Ukrainians released Tuesday put billionaire businessman Petro Poroshenko in the lead with 54 percent of the vote. Poroshenko, nicknamed the "chocolate king" for his chain of confectionary shops, was the only oligarch in the country to immediately voice his support for the uprising when it first began in November, long before Ukrainian President Viktor Yanukovych fled the country.

Former Ukrainian Prime Minister Yulia Tymoshenko is a distant second, at 10 percent of the vote. A popular politician known for her trademark hair braid, Tymoshenko was released from prison in February after serving two and a half years for abuse of office, but she hasn't been able to revive her base. Banker Serhiy Tigipko, an independent, is in third place with 9 percent. His support is strongest in the mainly Russian-speaking parts of eastern Ukraine, where, he says, Kiev's interim leaders have mishandled separatist rebellions.

Most of the candidates stand united in their campaign rhetoric. They have been highly critical of the interim Kiev authorities, and say that resisting further Russian intervention and fixing the Ukrainian economy are top priorities. If no candidate receives an absolute majority in the first round of voting on Sunday, another round with the two highest polling candidates will take place on June 15.

Regional rebellions are creating major problems for a smooth election.

The good news is that candidates have campaigned with minimal interference from separatists, and there have been few formal complaints about election law violations or intimidation of voters, according to the National Democratic Institute. The bad news is that several presidents and vice presidents of local elections commissions have been abducted, according to the United Nations, and their captors are unknown. 

The eastern regions of Donetsk and Luhansk have been taken over by pro-Russian separatists in recent weeks, and they are refusing to cooperate with local authorities and leaders. Kiev has attempted to regain control, leading to bloody clashes. If the rebellion disrupts election proceedings there—as expected—as many as 2 million people could be deprived of their right to vote, according to Ukraine's electoral commission.

And Kiev's interim leaders can't do much about that.

"We clearly recognize that on the vast territory of the Donetsk and Luhansk regions there is no way to hold elections in a normal way," Ukraine's Interior Minister Arsen Avakov said Monday.

But they're going to try.

Kiev politicians have been meeting and coordinating with regional groups in the lead-up to the election. About 1,000 election observers from the Organization for Security and Cooperation in Europe have been dispatched throughout the country to keep an eye on the ground. More than 55,700 police officers and 20,000 volunteers have been tasked to keep the peace on polling day.

Meanwhile, Russia is watching and waiting.

Russian President Vladimir Putin keeps saying that the 40,000 Russian troops stationed alongside Ukraine's border are pulling back, while the White House and NATO keep saying there is no proof of that. On Friday, Putin said that he would respect the outcome of Sunday's election, but the rhetoric from other Russian officials has suggested that Moscow may backtrack on that promise.