When i play say a spirit resource attachment card, do i have to put it ONLY on a spirit character? or can i put it on anyone as long as it doesnt say "restricted"?  thanks!

card in question is "unexpected courage" wanted to put it on Aragorn or Legolas.

You can put it on anyone.

Some attachments, like Support of the Eagles, have to be played on heroes with a particular resource icon.  It will say so on the card.

The word "restricted" is different, and not related to sphere limitations.  Characters cannot have more than 2 attachments with the Restricted keyword on them at any time.

gotcha, thanks! that helps greatly!

You only need to pay for it with the correct sphere resources (in this case, Spirit).  It can play on any eligible card.  In this case, Unexpected Courage needs to be attached to a hero as its only restriction.  It is not limited to a specific sphere (eg, Spirit).  Being Restricted does not restrict it to the sphere that "pays" for it.  It only means that a character may only have two attachments with Restricted keyword at the same time.

Edit:  Apologies.  Didn't see the previous answer.  My web-browser is slooooooow today and hadn't loaded the entire page…. oops