Need explanation please...

Hello All,
I am new to MFP and still learning the calculation to lose lbs.

Ex: calories in, burned and net......

Yesterday was my first day completing my food/exercise diary:

My goal calories is 1570
Food 1619
Exercise 604
Net 1015

Calories remaining 555

Can someone please explain how to read this? Much appreciated.

a widely sweeping generalization, but not knowing you from a pile of dirt...
The only thing you should care about is the calories remaining number (and probably your protein intake). Worrying about anything else is over complicating things. If you still have calories remaining, you should still be eating.

The activity part when MFP plans your goal, that should be your normal lifestyle not including working out?

Yes, that is how most people set it up.

Also, I noticed the protein intake MFP calculated was lower than what I am shooting for to build muscle.

I just discovered you can manually figure out a goal too. (took me awhile learning how to navigate here)

So if I want to lose lbs, I have to eat the remaining calories? (calories I burned, eat it again?)

Yes, you can change your macro goals manually (and most people probably should, imo). Once you get your dietary profile setup, yes... you should be eating those calories so that you NET whatever MFP calculates for you as your daily goal. As far as protein goes, most people need to increase their protein significantly and reduce carbs from what MFP sets as the default. You can increase protein and decrease carbs and stay at the same total calories, it just takes some playing around to get things where you want.