New Bike Questions

Hello all, so I have just bought a new bike (my first since I was a kid), and just finished putting it together (and even though it just involved the front wheel, saddle and handbars I'm still chuffed ).

So after doing that I thought I'd just have a quick spin up and down my street, and the bike is making a few noises I'm not sure about.

Firstly when I push down with my right foot, and it is fully extened the chain seems to be making a little noise (rattle?), and secondly when I brake I can hear the pads on the disc.

Now I figure the chain just needs lube (which I don't have as of yet so any recommendation would be well received), and the brakes wearing in. However since this is my first bike I'm a little worried about doing something wrong, or forgetting something, and thus watching it fall apart in my hands. So some reasurance on this would be helpful :oops: .