How can I start reading and saving the readings of the electricity meter in the apartment to the server?

Question

Smart House

There is a panel in the apartment with a conventional electricity meter (day / night), in the same panel I placed a server with Proxmox for work tasks, NAS, pfSense, I want to adapt it to the "Smart Home" theme, I want to start by reading the electricity meter. I understand that the topic is very extensive, do not tell me where to start digging? Do I need to change the counter or can I just deliver an ammeter to the circuit "after"? In general, I will be grateful for any links on the topic.
PS preferably budget options with the possibility of finishing by hand