The following is a hello world WinForms example:

    open System
    open System.Windows.Forms

    let form = new Form()
    do form.Width  
              
If you save the above as
              
    devsrchelloforms.fs
              
then assuming fsc is in your path, you can compile and run it as follows:
              
    cd devsrc
    fsc devsrchelloforms.fs
    helloforms.exe