
For Ecliplse and Java JDK, download the "Zip" file versions. In general choose software that's about a year old. Instead, look for the link for prior versions. When you go to a web page to download software, almost all guidance will point you to the link for the latest version. Don't use the latest versions of software. Most development organizations will develop a standard suite of tools and versions, and provide installation instructions, partly because of the risk of encountering compatibility issues.
The reason setting up the platform can be a challenge is because you are using a variety of open-source tools, each of which may have compatibility or configuration issues with the others, depending on what versions you are using.
Setup of the Selenium platform can be a challenge.