Those strange white pebbles

[Cheveyo]

Are those a fertilizer or a type of plant food? I've got a big cup full of them from when I got my plant, and I'd like to know what they are and how to use them to my advantage. 
Also, I heard watering the soil with coconut milk is really good for the plant, if anybody could explain, that'd be much appreciated.   

[penumbra]

Those white pebbles are called Perlite. They are generally mixed in to soil to keep it loose (prevent compaction) and aerate the soil. My first plant came in a cup of perlite--  when i moved my plant to soil i left the perlite on the roots as though it was soil. I don think that does any harm.
I've never heard anything about watering with coconut milk.....try it if you have a plant you dont mind losing.

[Arcygenical]

I'd think coconut milk would promote bacterial/fungal activity... Not something I'd want to do... I think you might have heard of mixing in coconut COIR with your soil?

And yes, it's perlite, a very light, heat expanded rock that holds a ton of water, and promotes drainage. I mix my soil 1:3 where 1 is perlite, and 3 is organic topsoil with natural nutrients.

[penumbra]

I tend to do 1:1:2 -- perlite, vermiculite, and potting soil respectively