Each machine that wants to install the application will need a developer license. See this page for some details.
When you have your app ready:
- select Store->Create App Package
- Select Build a package to use locally only
- Follow the prompts
This will create a package in whatever folder you specified. You should be able to copy that to another developer-licensed machine and install it.
There will be a batch file called Add-AppxDevPackage in the directory. Running it will install the app. It must be run as an admininistrator.