New Carmona bonsai

Hey everyone, any advice to help keep my bonsai alive and healthy would be appreciated!

This is my first bonsai, I live in the UK, coming into winter. I was told that this tree is roughly 15 years old. That radiator is never on.

I am considering an indoor light but I don't have a clue how powerful it should be, any light would be better than none? I am considering the following; should I open the window as much as I can or use a fan?

https://www.amazon.co.uk/dp/B07VKHQ..._dl_WGTA4ZCMVP39YG0PRPM8?_encoding=UTF8&psc=1

Would buying a humidifier help?
I have just bought some stones, filled with water to use as a humidity tray.

Would you say this tree needs pruning, if so where would you start?

I have had a lot of dry yellow leaves which just fall off really easily. Could this be because its the end of Autumn? Or is it an evergreen?

There is a spider living in it which makes daily webs. And I have seen sign of insects in the soil, maggots?