In PD, how do we make a preset work? I want it to work especially for toggles. Does anyone know how to save a state of a toggle as X when patch is loaded? And save several states?

if you right click or cntrl click on a toggle
and select Properties
you can click the button that says "No init" under Parameters
so it changes to Init
when you save the patch it should store its state. (*this also works for sliders radio buttons and the Number2 number atom Shift+Ctrl+N.)

you can also look in the Help Browser at 5.reference/savestate-help.pd

of course if you want to make sure it opens the same way every time regardless i would just use
[loadbang]
|
[1( or [0(

as far as more general state saving techniques there are many methods to do this.

For a simple preset management use ; messages. Use the receive options on your buttons to your advantage. For example let's say you have four toggles receiving on b1, b2, b3, b4 respectively. Then you make a message box like this: [;
b1 1;
b2 0;
b3 0;
b4 1; (
The semicolons are important!. Now you that message will set all those toggles whenever you bang it, without connecting chords for the toggles.

If you're having a lot of toggles you might wanna look into ad-da conversion / binary to decimal and back. This way you can (theoretically) keep track of 32 zeros and ones with one float. There are a couple of conversion patches in the abastractions forum.

As for working with arrays for preset management, take a look at the help files, and the array examples in the /doc/ folder to get an idea what you can do with tabread and tabwrite.