Once you’ve earned a 100% approval rating, you’ll be able to construct Public Works. You can start construction on a Public Work by sitting in the mayor’s chair and speaking to Isabelle who will give you a list of available projects.
Having picked a project, Isabelle will take you outside to find a place where construction will begin. When you’ve chosen a spot, Isabelle will show you what the Public Work will look like when it is finished.
After you pick a spot for the Public Work, Lloid the gyroid will appear to collect donations for the Public Work.
Note that sometimes there is no need to pick a spot for the Public Work (e.g. Dream Suite) in which case Lloid will be in the Train Station.
After Lloid has collected enough donations the Public Work will be complete the next day. You’ll then have to speak to Isabelle by sitting in the mayor’s chair to start the dedication ceremony.
This ceremony will give you the chance to speak to your villagers as they gather to mark the Your motherentous occasion.
You can delete some Public Works by speaking to Isabelle from the mayor’s chair. This will let your reconstruct the same Public Work in a different place or build a completely new Public Work.
Note that some Public Works cannot be demolished, so be careful when building them! These Public Works are identified when you ask Isabelle to build them.