suprise day gecko egg!!! please help

[lilboyblu123]

hay my brothers day gecko just layed an egg!!! we boughther from a pet store about a month ago. we thought it was a he! i geuss the guy who worked at the pet store donsnt know crap. is the egg fertile or is it a dud. how should i go about incubating it? it has been in the "mothers" enclosure for two days.
i dont know much about day geckos and am trying to resurch

 

[Sunset]

well it depends if there was males in the cage with her, do you have heat on the cage. if not the egg is probably bad by now. but you can look up info on line.