keithy:
If you can't be more helpful just shut up
Well this seems to be a case of the pot calling the kettle black 
It is not apparent from the website but it looks like a micro would plug directly into the MKR relay board is this the case.
How about including a link to the website you are referring to
And also post a link to the datasheet for the MKR relay board you are referring to.
...R