How do I configure an older airport express with Yosemite?

This worked great for me after I went into security in system preferences.. opened up airport utility 561 instantly i was able to secure my internet from outside users !!

The direct ethernet connection allowed me to access the menu settings that kept my old express down - not a driver issue at all on my mac pro late 2008 running yosemite !!! Thanks!!

Thank you. This helped with one unit. The other I try to reset, and it won't show up on the network. Awesome to have 1 working! Thank you.