How to use resistors?
You are mis-understanding both how Ohms Law works, and how current works.

Just because a power supply is capable of providing 1A it doesn't mean that it will force 1A through your circuit.

Your circuit will have an amount of current it requires to operate.  This is the amount of current that will be drawn from your power supply.  If it tries to draw more than the rated current of the power supply (1A in your case) then the voltage may drop, or you may damage the power supply.

As for Ohms Law, the voltage you should be using is the voltage drop across a component.  For instance, if you need to attach an LED at 2.2V and a current rating of 25mA to the power supply, you would use:

\$V_{diff} = 5 - 2.2 = 2.8\$

\$R = \dfrac{V_{diff}}{I} = \dfrac{2.8}{0.025} = 112\Omega\$

That would mean a 112Ω resistor would drop 2.8V when a current of 25mA passes through it.