I know that this is not an appropriate question for here. But I've looked everywhere, and cannot find an appropriate solution. What im trying to do is install CRM 2015 SDK on to Visual Studio 2013, to develop plugins, web resources etc.. I know its a stupid question , but can you please help.
The SDK for CRM 2015 doesn't include the Developer Tools (unlike the previous versions). They're to be shipped at a later date (AFAIK they still haven't picked one).
Microsoft says you should be able to make do with the 2013 version, if you update the DLLs references from the 6.x to the new 7.x version ones. Also, you'll probably have to toy with the target framework (CRM 2015's plugins must target .NET 4.5.2).
I personally gave up on the Developer Tools a long time ago, and have gone back to building Class Libraries, since I have to tweak 2011, 2013 and 2015 environments, both on-premise and online ... and multiple Dev Tools setups don't "stack" nicely on the same VS installation.