How to use software serial library just in one board and one port?

Hi, i need the arduino to communicate to both the processing sketch and also the IR receiver using the IR remote library(which uses the serial too), so i think i need to use the software serial library.

But i didnt figure out how to use that library.
I used the serial for p5, and the mySerial for the receiver. P5 works fine but the receiver didn't, the serial monitor seems to be occupied by the serial only.
To make it simple, i stop using the IR, and use a LED instead. LED as the output, a button as the input, when button is pressed, LED lights up.
But it didn't light up.

I noticed that software serial use pin 10 as RT, and pin 11 as XT, so i then connect the button to pin 10 and the LED to pin 11.
This time, the LED lights up no matter what. What's going on?

Anyway, how to use software serial just in one board and one port??
Thanks.

and also the IR receiver using the IR remote library

Which one?

which uses the serial too

That would be VERY unusual.

I noticed that software serial use pin 10 as RT, and pin 11 as XT, so i then connect the button to pin 10 and the LED to pin 11.
This time, the LED lights up no matter what. What's going on?

You seem to be completely unclear in what serial communication means. The switch and LED are not serial devices, so using SoftwareSerial to read from, or talk to, them makes no sense.

this IR library: GitHub - Arduino-IRremote/Arduino-IRremote: Infrared remote library for Arduino: send and receive infrared signals with multiple protocols.
i felt weird when seeing its example always with the Serial.begin() function.
Inside its library documents IRremote.cpp, i found many Serial.print() in it.

i am an absolute beginner and have no clue what a serial communication should be, so if LED and button is not, what else can i use to test the second serial created by the software serial library?

this IR library: GitHub - Arduino-IRremote/Arduino-IRremote: Infrared remote library for Arduino: send and receive infrared signals with multiple protocols.

That most definitely does not use Serial to read anything.

i felt weird when seeing its example always with the Serial.begin() function.

Generally, because the sketch wants to show you the data that it got from the sensor(s). That happens via the serial port and the Serial Monitor application. It doesn't mean that the Serial instance is talking to the sensor.

and have no clue what a serial communication should be

If you have a device that uses serial communication, like an XBee, a GPS, or a serial LCD, the documentation for the device will tell you that, and will tell you the baud rate, parity, start bits, etc., and the protocol involved. That is, what you need to tell it and what it will tell you.

what else can i use to test the second serial created by the software serial library?

So, you don't have another serial device you want to talk to. I'd skip that chapter in the book until you do have a serial device you want to talk to. By then, I'm sure that chapter will make a lot more sense.