You can change the permissions of your stack to determine who can open it and whether it shows up in searches.
To do this sign-in and open your ePoster as usual, but do not click on the Edit button. Instead next to the Edit button you will see the access permissions button that indicates what permissions your stack currently has (Private, Restricted or Public). If you are still developing the stack then it is probably still set as Private. If the conference has just finished then it is probably set as Public.
Click on that access permissions button and you will see the drop down menu allowing you to change the access permissions for your stack.
If you are still working on the stack but want to share it with others (perhaps your co-authors) so they can see what you have done, then you should change the permissions to Public and Hidden. This will mean that only people who have been sent the QR code or web address for your stack will be able to open and view it.
If the conference has finished and you do not want your stack to be accessible any longer then you should change the permissions to Private.