You can be done if you want. You don't need a pocket but if you want one it is already cut out and easy to sew back on. I felt because of the ruffled collars and the ruffled sleeves I wanted some straight lines on the shirt to distract from the frill. It is a design preference and you certainly don't have to follow my preferences. You can make your shirt how ever you want. If you want a pocket this is how you do it. Place your pocket where you want it. I placed it here between the darts. Make sure the pocket is straight.
There is a better view. Make sure your pocket isn't too far up or too far down.
Then you are going to sew it back on. You may be able to see the stich marks from where you seam ripped it off. If not, then this diagram should help. Start and 1 and end at 5.
This will be your starting point. I don't have a picture of your ending point. Once you hit it you are done. Done and you completed your first refashioning and it looks good enough you are going to wear it to the office on Monday. HOT! I promise you will love this shirt longer than any shirt you just picked off the rack at the store. I promise you would have spent the time you took to make it trying to find a shirt that fits this good and looks this good.