Alan
If you are using a DVD-RW or a BD-RE disc and it has content burned to it already, you should be able to use those discs again, but the new content will overwrite the old. It will not add to it. Typically the routine is (a) insert the disc (b) get the message that the disc is not empty, and program asks permission to erase (c) you indicate yes (d) disc is erased (e) new burn to proceeds.
For burn to folder DVD-VIDEO on DVD disc - you use only the whole VIDEO_TS Folder.
For burn to folder for AVCHD on DVD disc - you use only the whole BDMV Folder.
A pre-written to DVD-R and BD-R cannot be written to again in Premiere Elements. And, the program does not offer to erase and reuse.
However, the following may make for some interesting reading on Disc Finalization in Premiere Elements.
ATR Premiere Elements Troubleshooting: PE12: Disc Finalization
ATR
