Transfer ETH to UDOO

Hi all.
I just started with Metamask and in Order to transfer my Udoo from an “exchange” to Metamask I bought some ETH in Metamask in order to create a Udoo ‘wallet’ in order to be able to transfer them.
Now I want to transfer the ETH from Metamask to the UDOO in Metamask. How do I do that?
Thanks a lot