Once you click start in the settings on the left, a choropleth map of a state election will be displayed. Guess which party won, which year the election was held, and by what margin. Enter those in the boxes on the left. Then click guess and see how well you did.
On the homepage, you will have the opportunity to change a few settings to decide which map you are provided. The first dropdown allows you to choose which states you want to play with. For example, if you are familiar with the politics of your home state, you could only choose it. Conversely, if you are familiar with the politics of every state, you can leave it blank or select everything. The two input boxes below allow you to chose between which years you want to guess. For example, if you are only familiar with elections in the 21st century, you could choose 2000 in the first input box and 2024 in the second.
If you click with default settings, a choropleth for a random state election across the country will be displayed for you to guess. If you want to make the game a bit easier for yourself, pick a state or multiple states you are familiar with in the settings and you can narrow down the min and max dates which the election is chosen from.
Try looking for areas of the state with high population and see which side won. For example, in Illinois, Cook County (home to Chicago) and the Collar Counties that surround it contain most of the state's population, so, typically, if a candidate wins both Cook County and the Collar Counties, they win the election.
It's hard to get exact answers with dates, but if you look carefully, you may be able to get an answer within 5 years of the correct one, or at least within the same party system. Look for areas that have changed their voting patterns over time. For example, in Texas, the Democrats have dominated the Rio Grande Valley until very recently (2020), so, if it seems like the Democratic candidate only narrowly won the valley, the election was probably more recent.
This is a bit more difficult, and really is best learned with practice. For starting, look for the winner's vote share in the high population areas. If it is in the 50s or 60s, that usually signifies a 0-5% margin, while anything larger signifies a larger margin.