The Quick Start Guide is always a good place to check. It will walk you through step by step what is necessary.
An ASA however should by default give you an "asa" prompt. "sensor login" would be expected from an IPS appliance or IPS module on an ASA. See information here for details on that scenario.
Hope this helps.
Learn, share, save
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.