ch = chain, dc = double crochet
The photo above shows four chains made in the top part of the photo, indicating which chain is the fourth chain (in which the four double crochet will all be made) and "4 dc in 4th ch from hook" shown completed in the lower part of the photo. Yes, all four dc were made in one single chain. The other three chains (of the beginning chain-4) form what counts as another double crochet (see on the right-hand side of the stitches) so that there is a total of five double crochet.
This photo can be helpful to anyone who has not made multiple double crochet in the 4th chain from the hook before. The concept can seem confusing when coming across those instructions in a pattern for the first time but this photo can help to clarify what it means.
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