What are these? white dot, red arrow & click button for $1

Sorry, I'm very new and confused.
What is the little white dot that hovers above my avatar's head?

Periodically I see a fat, small, RED arrow pointing to something. If I click on it it disappears. Why is it there and what am I supposee to do with it?

I see people with white print in front of them: Click me fo L$1.
Other people have L$1 button hopper in to of their name.
For both of these, why are they there? How do you collect $1, if that is the meaning?

The white dot is an indicator that you're actively connected to the voice chat function. It will turn into green lines if you are actually sending your voice. It's typically push-to-talk, so if you don't wanna be heard, don't worry. (^_^)

The red arrow is an indicator of a selected map location. You probably got the properties of a landmark or clicked somewhere on the map. It's pointing in that general location as if it were a guiding beacon. (^_^)

And the click me for monies stuff is usually a scam. (=_=)

Thank you for taking time to help me.

In addition:

To change your voice chat preferences, go to Edit/Preferences/Voice Chat.

That "click on me" thing is supposed to pay you one LINDEN dollar, not $1.00. The current exchange rate is about L$270 = $1 US. But don't bother, even for such tiny amounts...it's usually a scam to get you to visit a location, or sign up to take online surveys, or some such.