Is that the one that was linked?
No, that's the service manual that I linked.
The technique is referred to as the "rubber band trick". Use the forum search function and you'll find a bunch of references and descriptions of it (include the quotation marks so the search is for the complete phrase).
In short, you use rubber bands over the top of the valve cover, the end loops of the rubber bands go down through the tappet-cover holes and the wrap around the valve lifters. This holds them up, away from the valve stems in order to keep them from binding as the cover is being maneuvered into position.
It is also important to fully back-out the valve adjuster (the nut-screw combo) so that there is the maximum possible clearance between the lifter and the stem.
Cheers