What is the name of this outfit? If I have it, I will test it.  I always merge into scene if that is an option. If there  is a hat I apply the hair before dressing the character. If there are no options in the parameter tab to assist with adjusting the clothing that is when I use Mesh Grabber from the Daz Store. If you are going to get it, I recommend you get the bundle or all the parts in the bundle. 

Here are the steps I use

1. Select the character

2. I then right click on the outfit in the content tab, and merge into scene

3. I fit the outfit to the character, and parent it as well

4. Make adjustments in the parameter tab if there are any available.

5. Use Mesh Grabber if needed. I prefer to use the wireframe viewpoint, it makes it easier to work with the item.