The last step that is necessary towards completion is to wrap your compiled algorithm class (and all other classes that you wrote for your algorithm, if there are any) into a jar archive.
It is important that the archive has the same name as your Membrane Packing Algorithm class. So if your class is named, for instance "MyMembraneAlgorithm", then the name of the jar file you put it into has to be "MyMembraneAlgorithm.jar". Otherwise it won't be accepted.
There are multiple ways how you can create this jar. The best way is to write a small script that builds the archive and copies it to a specified location, especially if you have to test your algorithm often during development. Or if you are using Eclipse, you could use its export function in order to build a jar file of your resources at a specified location.
As soon as you are finished with this step, your algorithm should be ready to be imported into the MembraneEditor (see how to import external algorithms into the program).