Following umintsuru's method, I washed it in gently soapy water and blocked it to dry. Surprisingly, it turns out to be nice cotton - not bad for the dollar store!
The edging is simple - Bessie Attenborough's design, enabled by Diane's suggestion to find her book. Thanks, Diane - worth the book for sure.
Tatted in #40 Lizbeth, the task went by very quickly, completed in two evenings, and I didn't have to sew the thing on, thanks to the 'attach as you tat' method. Makes sense to me, though I could not do that with an Iris Niebach pattern or one that is as intricate as hers are; it would be much too exacting.
That having been completed, I have embarked on a new pattern not tatted before that shows promise; next time there will be beads! I am emptying the shuttles and this is what I have for now: