Short answer
A saju chart has four columns (most Korean charts show hour, day, month and year from left to right), each with a heavenly stem on top and an earthly branch below; start with the top character of the day column, because that is you.
The layout
Korean charts usually put the year on the right and the hour on the left, so you read them right to left: year, month, day, hour. Each column is a pillar. The top row holds the heavenly stems (ten possible characters like 甲 or 庚), the bottom row the earthly branches (the twelve zodiac animals, like 子 Rat or 午 Horse).
Step 1: find yourself
The day stem, top of the day column, is your birthday type (Day Master). Everything else is read in relation to it. If it is 丙, you are the Sun, and the rest of the chart is your weather.
Step 2: count the elements
Each of the eight characters has an element. Count them. A chart heavy in Water and missing Fire reads very differently from a balanced one, even with the same birthday type. Our readings note what you have too much of and what is missing.
Step 3: notice the relationships
Stems and branches combine, clash and support each other. The day branch (just under you) is traditionally read as your partner seat. These relationships are where saju gets deep; the glossary explains each term in plain English, and the 60 day pillars show how your day column reads as a pair.
Or skip the homework
The free check does all of this for you and shows your type and day pillar.
FAQ
What are the four pillars in saju?
Year, month, day and hour. Each pillar has two characters, a stem and a branch, for eight in total.
Which pillar is the most important?
The day pillar, because its stem is you. The month pillar is often read as the season you were born into, which strongly shapes the chart.
Why do Korean charts read right to left?
It follows the traditional vertical, right-to-left way of writing. Many modern apps show it left to right; the content is the same.