Hi allI am thinking about buying my first home.While inspecting...

Hi all

I am thinking about buying my first home.

While inspecting the property i noticed an access point to something ( don't know what) which led me to the question:
What is this?
Which led to the next question:
Who do I go to to find out what this is?
Which led to the next question:
What else should I be asking/ checking before I make an offer?

Can anyone with experiences buying house give me a quick run down on what I should be doing, people/organisations I should be talking to and what questions I should be asking?

Much appreciated.