spacers

Hello , Im a newby to the forum, Im restoring an 89 tdub, Ive been reading all the posts about using spacers on the forks , but I have never taken the forks apart yet, so know very little, Im just looking for a tip on where the spacer actually go inside the forks, are they dropped into the bottom of the tubes below springs? Or are they installed at the top of the forks somehow? I know it seems like a lame question, but I dont see any info. posted about it. Thanks if you can assist.