Before download and install IntelliJ IDEA for Java developers you have to install Java JDK on your windows. For that check this How to Install Java JDK 9 on Windows 10?
Install IntelliJ IDEA for Java Developers
In this section, we’ll discuss the steps to Install IntelliJ IDEA for Java Developers on Windows 10. Here we also included a video tutorial, if you find difficulties to follow the steps mentioned below.
Step 1: Open any browser and Search for IntelliJ IDEA
Step 2: Open the website: https://www.jetbrains.com/idea/
Step 3: Click on the download option and download the community version, which is a free and open source.
Step 4: After that open the downloaded file and install it, as you install other software on your windows 10.
Step 5: Open the IntelliJ IDEA and from the left-hand side select Java and on Project SDK choose your Java JDK location and click on Next.