Does anyone know how to merge data from multiple columns into one? I was able to merge 2 but I cannot merge more than that.

There is a video and text tutorial available on the wonderful and informative WF-Pro.

Just keep doing the same thing! The new column you want to merge (the mergee) should always be to the right hand side of the thing it's merging into (the... merger??). Edit the merger, and add sharecol=true to the bottom AND its column number (the final line in the merger should give you a clue as to what number to use).

e.g. your new line might look like this: column.4.sharecol=true

Pray you don't accidentally merge something out of order, as it's a bit of a pain to separate a merged column. (basically involves finding the correct sharecol=true line to delete)