Introduction
After a quick onboarding that brought me up to speed, getting me to know about the issues that the product was facing at the time, the Head of Product and I conducted several brainstorming sessions to decide on the best medium to test the product-market fit and primary/secondary features. We concluded that a Slack app would be the ideal medium as it is easy to prototype, it is relatively quick to develop, and, most importantly, most of our target audience would use Slack as part of their professional life regularly.
Two Forms of Availability

Around the time we had just started working on this Slack app, we considered two different forms of availability that I called "local availability" and "global availability".
Local availability: A person would be locally available when they signal that they are available to the people who sent meeting requests at a prior date or to a pre-selected group of people. This could be called "selective availability" as well.
Global availability: A person would be globally available when they signal that they are available to everyone. This could be called "unselective availability" as well.
The reason why we considered this concept of local availability was that in some very large companies, signaling that you are (globally) available to everyone on your Slack channel means that hundreds of people would be able to request meetings, making it extremely hard for the user to maintain.
For reasons that I was not informed of at the time, we were asked to quit working on the Slack app and move to work on the iOS app that the company was already developing at the time I joined.

One of the last prototypes I designed to showcase how this Slack app would work.