how do I scrink a document to a single page

Hi Don

Thanks for reaching out in the community. The dotted lines on your document represent page breaks. Check to see if your content crosses any of the dotted lines on your document to see how many pages are being used. If you want to shrink it to one page select all the content (Windows: control + A or Mac: Command + A) and resize the content so that it is within only one page. (not crossing any of the dotted lines.)  I hope this helps!

On the other hand if i have crossed the lines and want my diagram to be over 3 pages but it is squashed into on and too small to read what can i do??

Thanks for reaching out in the community. Go to the right side of you page to page settings and ensure that the auto-tiling toggle looks like the picture below.

Select all of your content using (Windows: control + A or Mac: Command + A) and drag it across the page as seen in the picture below. 

I hope this helps! Thanks for using Lucidchart!