docs: add link to the Go installation guide

README.md

@@ -83,6 +83,8 @@ Read the [Changelog](https://github.com/Microsoft/vscode-go/blob/master/CHANGELO
 
 ## How to use this extension?
 
+This extension requires the `go` tools. See [Go's installation guide](https://golang.org/doc/install) for the download/installation instruction.
+
 Install and open [Visual Studio Code](https://code.visualstudio.com). Press `Ctrl+Shift+X` or `Cmd+Shift+X` to open the Extensions pane. Find and install the Go extension. You can also install the extension from the [Marketplace](https://marketplace.visualstudio.com/items?itemName=ms-vscode.Go). Open any `.go` file in VS Code. The extension is now activated.
 
 This extension uses a set of Go tools to provide the various rich features. These tools are installed in your GOPATH by default. If you wish to have these tools in a separate location, provide the desired location in the setting `go.toolsGopath`. Read more about this and the tools at [Go tools that the Go extension depends on](https://github.com/Microsoft/vscode-go/wiki/Go-tools-that-the-Go-extension-depends-on).

docs/Go-tools-that-the-Go-extension-depends-on.md

@@ -1,4 +1,7 @@
-The Go extension for Visual Studio Code offers various Go tools that are installed in the user's GOPATH. Some of them are responsible for general language features like code navigation, auto-completions, symbol search etc. Others, while helpful, are optional for the Go extension to provide day-to-day language support.
+First, the Go extension for Visual Studio Code requires the Go tools to be already installed.
+See [Go's installation guide](https://golang.org/doc/install) and ensure the `go` command is available from your [`PATH`](https://en.wikipedia.org/wiki/PATH_(variable)).
+
+The Go extension for Visual Studio Code offers extra Go tools that are installed in the user's GOPATH. Some of them are responsible for general language features like code navigation, auto-completions, symbol search etc. Others, while helpful, are optional for the Go extension to provide day-to-day language support.
 
 Below are the tools essential for the general features of this extension. If you have chosen to use the [Go language server](https://github.com/microsoft/vscode-go#go-language-server), then most of the below tools are no longer needed as the corresponding features will be provided by the language server. Eventually, once the language server is stable, we will move to using it and deprecate the use of individual tools below.