I am going to try and make this as simple as i can since I'm new to making tutorials so hopefully everything goes well.
I'm using Visual Studio as my IDE, If you don't use it i recommend you do so everything is relevant to this tutorial, You can download Visual Studio Express C# from the link below.
Visual Studio Express
Next you will need OpenTK from their website, I recommend downloading a nightly build so you get all the newest features and help with issue tracking if you are into that.
OpenTK Website, Latest Build
Setting up the Project
Open up your version of Visual Studio and click New Project on the left pane
or (File > New > Project).
In this window you want to select the default 'Windows Forms Application' if not already selected,
Then name the project, Alter the location if you so choose, And click OK.
Now we have the project ready to go, the first thing you want to do is Right-Click References in the right pane, and select Add Reference this will open a new window, Click the leftmost tab '.Net' and scroll till you see OpenTK (May need to load before it shows up) there are two other references here
OpenTK.Compatibility and OpenTK.GLControl don't bother with these they wont be needed.
Now that the reference is added to are list we can go ahead Right-Click Form1.cs > Delete as we are not going to be using the windows forms system, with that out of the way we can start coding :D
Initial Window Setup
Ok in your Solution Explorer Right-Click your project and Add > Class this will open a window, where you can name the class, I'm going to name it Main.cs and then click Add it will show up in the Solution Explorer.
Onto Program.cs where we will reference main and get the program running, below is how it should look.
The parameter 60.0 in Run() is for OpenTK.GameWindow - how many intervals before we update, This is are Updates Per-Second not Frames Per-Second we don't want to limit FPS.
Now you can save Program.cs (CTRL+S) and open up Main.cs where we get to the guts of are GL program.
Are Main class is pretty bare bones at the moment there are a few things we need to do here.
reference OpenTK and extending the GameWindow, initializing as a 800x600 window.
Now we override some methods from the base class.
Basics and Viewport
Here is a basic setup, drawing a quad.
And i believe that's all it takes to a basic setup.