Crochet "in side" of stitch

I have just begun to crochet the outside frame of a dresser scarf whose center is a series of assembled medallions. The first round of the frame consists of chains with the occasional tr or dtr attaching it to the medallion pieces. The corners of the first round are composed of (dtr, ch7, dtr) and the first round ended with a tr in the fifth ch of beginning ch-19 to form the last loop.

My question is about the instruction for round 2 of the frame. Having just completed the first round as above, it says: Ch3, 3 dc in side of same st. What does "in side" mean -- through a front or back loop? I am assuming it doesn't mean "3 dc in same st" because I did a lot of shells in the same stitch while forming the medallions, and they didn't use the wording "in side." Any help will be appreciated.

Forums: 

While CYCA forums were so terribly beset by spammers, serious answers to serious questions were getting swallowed up in advertising. The problem seems to have been addresses for the time being. My post telling you that your answer had been diverted to another site was also deleted when the spam went though, so here it is:

Since your last join is with an elongated (tr) stitch, it seems that it is that stitch that is being targeted for working down the side. In other words, work three dcs in the little spaces formed by the wraps of the treble. This will probably match up with some similar group of stitches later on in the round. It would be helpful to see what comes next, but this would make sense. A graph would be great! Do you have a picture we could look at, or a site with directions?