SAP and Eclipse foundation both together provide a very easy way to install ABAP Development Tools(ADT) on Eclipse. The Steps provided below, are applicable not just to install ADT but also other SAP tools like HANA Native Development tools, HANA modeler, Mobile Development Tools etc.
Refer to https://tools.hana.ondemand.com/ for SAP Development Tools for Eclipse. You can easily figure out that not only ABAP but BW, Cloud, Cloud Integration, HANA, IDM, Mobile etc. tools are available here. A clear availability matrix is also provided if the Development area is available for particular Eclipse version.
The time this blog was written, Eclipse Oxygen was the latest version and development tools could be downloaded using URL https://tools.hana.ondemand.com/oxygen
Follow steps to Download and Install Eclipse on your local Desktop:
Step 1. Download Eclipse: Eclipse should be downloaded from eclipse.org. Just web-search the Eclipse version you like to download and download it. Select 32/64 bit versions cautiously as it must match the JAVA-JRE bit version installed on your system.

You need to download JRE if it is not available on your machine. A simple method to check JRE bit version of your Windows machine is to go to Control Panel and Search Java:

Step 2. Downloaded Eclipse has a base version of Eclipse and SAP tools are not yet present on it. Go to Eclipse > Help > Install New Software
Step 3. Enter “Work with” update site as per downloaded Eclipse version. e.g.
if Eclipse Oxygen version is downloaded then https://tools.hana.ondemand.com/oxygen should be entered
if Eclipse Neon version is downloaded then https://tools.hana.ondemand.com/neon should be entered

Step 4. Select required components with checkboxes and Click Next
Step 5. Accept License agreement and Finish
Step 6. Once installation finishes, Restart Eclipse!