Some beginner questions

Forgive me if I am being a bit stupid but this is my first time getting a laptop in a while so I've settled on the ThinkPad t480, I will be using it to just browse the internet, watch films and stream on discord. No gaming or programming

I am planning on installing Linux on it, probably Ubuntu

I want to ask:

1. How easy is it to replace and fix parts on the t480? For someone who has no experience in laptop repair
2. Are e-commerce sites a reputable place to get one? (For SEAsians, I'm planning to get one on shopee)
3. What are some key things I must look out for while buying one?
4. If you think that the t480 isn't a good match for me, what other models would you recommend?