A mana node sits in the open on Seafarer’s Peak, one of the easier ones to reach and one of the ones the Xeochicatl come for.
Where it is
Seafarer’s Peak. The marked map is on the location page: Seafarer’s Peak.
Getting it
Nothing to it. Walk up to the node and use it. Stand within three squares or the meld will not take.
Melding
Stand within three squares of the node and use it. The bond raises your maximum mana by three points plus one for every ten points of Mysticism above five, so between three and eight depending on how mystical you are. You can bond with each node once, and the game will list the ones you hold if you ask.
This node can be drained by the Xeochicatl. See Nodes for what happens when one is attacked.