Setting up a render target can be tricky and only works when running in DX11 mode, but here is a graph example:

Note that to access some of the options you need to enable Settings / Advanced Mode

Make sure the Texture Component node and Texture Map both use the same UniqueName.
Select RenderTarget as type and set the size and format on the Texture Component node.

On the Pass node, there are a few settings you can define as well, most are optional depending on how you plan to use your targets.