[seL4] handling timer with camkes

Dear all, I would like to build a scheduler on top of camkes. I figure that I have to get access to the timer irq and start from there (e.g. then, dispatch other tasks according to the number of elapsed ticks). I did find some relevant examples, especially in the camkes-vm ( https://github.com/seL4/camkes-vm) but nothing I can try. Is there any information about such materials? I tried to reuse the component but always got build error. I was wondering if there was an existing tutorial or an example I could try that will help me. Thanks. Julien.