We always welcome contributions! Feel free to update our pages. Don't worry too much about whether it's good enough: we'll finish the details if necessary.
The page http://doc.grid.surfsara.nl/en/latest/Pages/documentation/ describes how to contribute.
If you're still unsure how to submit your contribution, you can just email it to helpdesk@surfsara.nl (please mention "Grid documentation") and we'll take care of it.