For starters, Iowa Republicans must fulfill two requirements if they wish to attend their precinct's caucus: they must be a legal Iowa resident and a registered Republican, the Republcian Party of Iowa notes.

If someone wishes to vote in the caucus but is not a registered voter or Republican, they can register in person at their caucus location. To register on-site, Iowans will need a valid ID and proof of address. All caucus-goers will need valid forms of identification to caucus Monday evening, even if they are already registered.

What is more, those who are 17 years old but will be 18 by election day are eligible to participate in the caucuses.

One can find which of what NBC News reports are 1,657 precincts they belong to through this link to the Iowa Secretary of State's website, per the Iowa GOP. Voters can locate their precinct caucus location by going to this Iowa GOP website and selecting their county. 

Caucuses in all 99 counties will commence at 7:00 p.m. CT, and the Iowa GOP emphasizes caucusgoers should arrive early. 

As NBC Notes, caucusgoers elect precinct secretaries and chairs at the start of the meetings before supporters of the candidates give remarks.