How to render to texture instead of screen in OpenTK?

Question

OpenGL

I need help. I wrote a computer game in Xamarin. On older android phones, it does not work as fast as we would like. To improve performance there is the following idea. Before some objects begin to move, some of the objects whose position does not change are drawn into a texture, which is then used to display on the screen and on top of which render objects that change their position in space. To do this, you need to figure out how to render an image to a texture.
Need two or three consultations, ready to pay. I ask a question on Habré for the first time. If such announcements are not welcome or there is a separate thread for them, then please do not kick, but guide where exactly to write.