The following pictures show you what it means when only the back or only the front loop is to be crocheted. The back loop is green and the front loop is red.
Example back loop: Instead of crocheting with the crochet hook through both loops (front & back), we only go through the back loop.
If you also want to crochet the front loop later, it may be useful to mark the beginning of the front loops. For example, with a different colored wool thread.
Example crochet front loop, if previously only the back loop was crocheted.
The sample images are from the patterns of the Surprise-Bell (currently only available in German).
