You could jump temporarily to the Share/Disc/DVD section and its burn dialog (with DVD disc in DVD burner tray) and see what the burn dialog Quality Section shows for Space Required and Bitrate (check mark is next to "Fit Content to Available Space").
As reference points:
For a DVD-R, 4.7 GB/120 min. stated capacity with 4.38 GB actual capacity.
Often I have seen a maximum of 90 min suggested for Timeline content, stated as for "best results".
8.0 Mbps (megabits per second) is the maximum Bitrate offered for Premiere Elements Variable Bitrate part of the burn preset. Anything lower than 8.0 reflects the program lowering the Bitrate to make the fit. Typically, as the Bitrate is lowered, the quality is lower.
Please check out this possible answer to your question and let us know if that worked for you for what you want to do.
I did as you suggested and put in DVD and unchecked "fit contents to disc"and nothing happened when I moved slider up to best quality? so is that OK?
In Timeline is the time shown the actual time that will be on the disc?
also is the size of the project file the actual size that records to disc?
I am new to this program and finding information to some of the basics hard to come across.
The Duration for your Timeline is exactly how long the Duration of the output file will be, whether to DVD, BD or to an AV file.
The Project file (PREL) size has zero bearing on the Duration of the Timeline, or the size of the output file, in any format. It is nothing but an XML database with links and instructions.
As has been stated, and approximate 70 mins. Timeline, shown as 01;10;00;00 (hours; minutes; seconds; frames) will fit nicely. I normally use 90 mins. at my max, and at about that point, begin thinking of two 4.7GB DVD's, or one DL 8.5GB disc. Much beyond that 90 mins. mark, the quality of the DVD-Video will really start to show, as the Bit-Rate is reduced to fit more time on it.