What do you know about dog's false pragnancy and what to do with that?

Are you positive it is a false pregnancy?

She has had no chance at all to be with a male dog?

If it is false then just let it runs its coarse.

She will probably start nesting and even find toys to have as "babies" and try to nurse them.
She may even develop milk.

It would be wise to get her spayed so you prevent things such as mastitis which is an infection of the nipple as well as pyrometra, an infection of the uterus.