Need Help with Extracting a Mask for a T-Shirt

Hi, I am trying to make a T-Shirt for my character in Bender 2.8. I am trying to extract a mask in Sculpt Mode but it is not working. I have looked for a Tutorial online but can’t find one that explains this. Any help would be appreciated! Thanks.

Step 1

Step 2 - (Go into Sculpt Mode and mask the area I want to extract)

Step 3 - (In Sculpt mode I select > Menu > Mesh Extractm and use the default settings)

Step 4 - (This is my result. I am not sure why it isn’t making a t-shirt out of my mask)
step 4

Ok, I got it working. I realized my mesh wasn’t dense enough.
mask_5