Xandi, in the Content tab, right click on the prop icon and select "Browse to file location", this will tell you what folder the file is saved in. Then go to File Import and search Daz 3D, Studio3, content, Runtime, Geometries, (folder you noted earlier). And just select the OBJ file.

Not really sure how Daz 4 works but I think it is -

Daz 3D, Studio, My library, Runtime, Geometries, (and the folder you searched for) and select the OBJ file.

Hope I got that right - John