How to properly organize the technical part for the implementation of VoIP telephony in an organization?

Question

Asterisk

I decided to abandon landline telephony (regular city numbers from RTK) in the organization and transfer everyone to IP telephony with a single number and employee code.
I would like to understand how to properly organize the technical part?
Planned:

1. Raise the Asterisk server and fasten it to some provider (eg mango office).
   
2. Buy Yealink W52P VoIP phones and a pair of wired Grandstreams.
   
3. Buy a Mikrotik CRS328 switch with PoE support (distribute power to phones) and scatter the patch cord around the building.
   

And then the questions came up:

1. Is this all enough for a full implementation? Or do you need some other equipment?
   
2. Is it worth it to take such a switch? The fact is that I already have such a switch, but it distributes the Internet and power to Wi-Fi points. Alternatively, you can connect phones to these points and distribute power through the power supply
   

Answer 1

1. It is possible through an asterisk, it is also possible directly through a mango virtual machine, in the case of an aster, you can directly purchase trunks from different providers to save money.
2. it doesn't matter with Aster phones
3. POE switch is useful if more than half of the ports are used on it, it also gives a plus of centralized power and the ability to connect the entire tangle to an uninterruptible power supply. Phones with b / p usually cost less than buying a poe switch, but there are some disadvantages
4. It is better not to connect phones to points