Hello guys i am new here

I just bought 3D printer Ender 3

So i have few questions.

1. When printing finishes do i need to leave the printer on for a while to cool down or can i just unplug it from power supply ?

2. When my printing is done , i always clean my bed with alcohol , do i need to clean the nozzle remove the fillement or something else and how ?

3. Do i need to store in plastic bag my fillement if i dont use it one week , and do i need to remove it from nozzle ?

4. And any suggestion , what parts do i need to buy, which first wear out ?

Thanks