You can allow users to schedule a time with you as long as:
You have set your schedule times by clicking on your profile settings and selecting schedulde
You allow a specific user to schedule a time with you by clicking on the $ in a specific conversation and enabling them to schedule time with you.
Users who had already your phone number on their phone contact list before joining Instantgo will be able to schedule a time with you by default. You can decide to disable that option by clicking on the $ sign in the chat conversation with them.