You have very basic questions. You should have a look in the "Strategies" section and in the miscellaneous FAQs e.g. in the "Encyclopedia".
Your amount of money is the treasury in the lower left corner. When it is red and starts with a "-" you are in dept . When you are deeper than -500 you can't spend anything anymore.
The important "Economics" screen can be reached via the "Domestic Policy" button. You have several sliders there.
One for your tax rate which generates your income (the second source is trade). It is directly related with moral which is very important. You should really read more about that.
The second slider is "Expenditures" and determinses how much you spend.
The other three sliders underneath determin where you spend.
The most commen beginner problem is that you buy stuff and get broke by the leases.
A common start is:
1) taxes as high as you can keep 100% approval (i.e. equal to moral), this is about 40-60%
2) expenditures at 100%, lower it before you would reach depth
3) military slider at 100%, research and social 0% until you build all ships needed for the initial colonization phase
This way you can build colony ships and scouts fast enough.