How to implement a task with geolocation?

Question

Yandex

Hello!
Here I was given a task.
We have a database of clients with addresses. There are field managers who are assigned to the n-th number of companies. Over time, the customer base grows.
What tasks the system should solve:
1) For the day, determine the optimal list of companies through which the manager must pass. (Metro + walk)
As I understand it. You need to take a list of all companies assigned to this manager, a starting point (he will go from home or from the office), calculate the distance between organizations (it seems possible through Yandex maps API) and select a chain of n organizations with a minimum distance. While it is difficult to think over the implementation, I would be grateful if you indicate in which direction to dig and what to read, because I am not very strong with algorithms.
2) When adding a new client, identify a suitable manager.
Here, as I understand it, you need to take the client's address and find the nearest existing client address, see who serves him and assign this manager to a new company.
3) If the manager has time, then show him the nearest addresses of clients, to whom else you can call.
This is probably a difficult task for me, but I am very interested in it and have a great desire to realize it!