How can I set up an appointment for the kitten package #3 ? I tried online, but didn't have the option for any package.

call directly to the office.

You just need to add a note in the comments section.

When I scheduled my cats neuter appointment online, there was a place for comments and I put in everything that I wanted done and then they emailed me a confirmation. You could try that or call them and leave a message because they do return your call within a few days.