First you need to have a premium account and some spare tier

If you've decided you'd like to donate please contact Wellington Beam for a group invite.

Once in the group, open up the 'My Groups' window using 'ctrl-g' or right click on yourself and select 'My Groups'

Right click on NCI Land Holdings and select 'View Info'

Click on the Land/Assets tab

Enter the amount of tier you'd like to donate in the text box. There should be a flashing cursor in it. The maximum amount you could donate without increasing your current tier level is indicated below the white box.