Dynamics 365 Developer toolkit for Visual Studio 2017 can be installed by following the below steps:

1. Download Dynamics 365 Developer Toolkit for VS 2015 from here.
2. Once it is downloaded, extract the content of it to a folder
3. Open the folder to which the content has been extracted and open the file “extension.vsixmanifest” in a notepad or text editor.
4. Change the version number number from 14.0 to 15.0 as highlighted below and save the file:
5. After changing, it looks like below:
6. Select all the content in the extracted folder (from Step 2 above) and zip it
7. Rename the file to a [unique name].vsix and save it. Click Yes on Rename pop up.
8. Double click on the vsix file created in the step above and click on Install.
9. It’ll show a warning for incompatibility with VS 2017. Click on Yes and Proceed.
10. Installation will be started for VS 2017.