To share steps across features you have 2 options that I know of so far. You can create a class that inherits from SpecFlow.Steps, give it a [Binding] attribute, and code steps as normal and they will be usable in all features in the same assembly. This is inherent in the global nature of steps in SpecFlow and you don’t have to do anything to get this behavior.
When you need to share steps across assemblies it gets a little hairy. Say you want a common set of steps that you use for every SpecFlow feature that you write in your entire development life. To do this you will need a bit of configuration. You would create your Common SpecFlow Steps project, create a step class like you did above, reference this project in the test project you want to use it in, then add this little number to the <specflow> section in your configuration file:
<stepAssembly assembly=”ExternalStepsAssembly” />
Just plug in the name of your Common SpecFlow Steps project and you are in business.