I’m having some difficulty editing fonts.
If the font is not one originally produced using Font Creator 5.0 you might have problems due to the nature of the font file.
I would suggest trying to produce, as a learning experience, a small test font entirely using Font Creator 5.0 and learn how to do what you want using Font Creator 5.0 to edit a Font Creator 5.0 font. For example, start a new font using Font Creator 5.0 and just add a few squiggles to, say, a, b and c to represent the barcodes and then proceed to try to move them upwards and add the letters.
When you are ready to have a go at a font to do the job, you could start up Font Creator 5.0 twice and start a new font in one of the two and open the original (non-Font Creator) font with the barcodes in it in the other of the two.
Then, using copy and paste, you could copy the glyph for b from the original and paste it into the place for b in the new font. It is possible to copy more than one glyph across at a time, by, say, highlighting p, q and r in the original, then copying then highlighting p, q and r in the new font and pasting. It can be done for many more than three at a time. However, if there are only a few it might be easier to copy them one at a time and leave learning to do multiple copying until a later time.
The result should be a font produced using Font Creator 5.0 containing the glyph information, but not the behind-the-scenes structure, of the original font.
Then, having saved a copy so that you can always easily go back to that stage if the need arises, the task of moving the contours of the glyph upwards and adding the extra parts can commence. One possibility is to import to an empty glyph and then afterwards copy the contours from that glyph and paste them into the glyph with the barcode, rather than do it all at once. I am not saying that direct importing would not work, I have not tried it, yet it seems a better technique to import to an empty place first: it also has the advantage that scaling of that imported item would be easier (if indeed scaling is needed) as scaling takes place on every contour within a glyph.
I hope that this helps.
William Overington