#Uber workings:Do you understand their scheduling?

[davey@mindly.social]

#Uber workings:
Do you understand their scheduling? I need to get gimpily downtown (for an appointment to have my operated-upon foot put back in use) Wednesday, and don't have a ride. I've a few questions.
1. Uber, unlike Lyft, seems wiling to pre-schedule a pickup, online, without needing to go cell phone. However, the software says "5 minutes from your location." Does this mean I have to locomote five minutes to get to them, or just that the driver would be starting out near me?
2. Can I say I wan't to get to my destination at 10:15 a.m., and leave the driver to decide the pickup time, or do I need to say, "Pickup time 8 a.m." to be sure that whatever route they take, there'll be loads of time.
3. Does the answer change if I select the shared-ride option? Is the latter viable given that I'll have a collapsible knee scooter to stick in the trunk?