New Orchid owner unsure if my plant has a problem

[misslexie_marie]

Hi my names Alexis.
I am new to this - Here's my story.
I always wanted an orchid, it is one of my favorite flowers to look at. This valentines day my boyfriend bought me one! I am really interested in keeping this guy but iv come across some things on the plant that I feel may be a problem.

1st there's a few light green, and one dark spot on some of the flower petals that seem to be in a pattern or alone. These spots are hard and are showing on both the front and back of the flower.

2nd Why is the leafs edges turning brown. Also one has a white hole indented in it.

3rd What is this stub and should I cut it ?

BTW I was told to water and feed my plant every two weeks I haven't watered it yet also I picked up Miracle Gro Orchid Food for when I do. How much water would you recommend?