Small Engines (Lawn Mowers, etc.): Trimmer, snags, spool

Question
Hi John, I have a Ryobi trimmer with two ports for line feed.  The line is "supposed" to be bump and feed.  For the life of me I can't figure out how to wind new line unto the spool and out the two ports without snags etc.. Is there any trick to do this line re-winding?
Thanx
Doug

Answer
  Most trimmer heads give confusing info as far as winding line, as they are made to both work on straight and curve shaft trimmers, which rotate in opposite directions.  But in both cases, the line needs to be wouund in the same direction, and when winding, i use a finger to keep the line seperate when winding.

so wind it up one way, if it doesn't feed, wind it the other way.