Newbie needs help

I have recently bought a 3d printer. It is a clone from China resembling the Prusa/Anet.

It didn't come with proper instructions.
It has a motherboard with 2560 written on it.

I have bought a Titan extruder and a E3D lite head as I want to improve the print quality.
I have spent many hours looking at you tube-films about upgrading firmware.
Everyone assumes the audience knows why they need to upgrade and already know their own firmware.

What i don't understand is, how do i know what i already have?

If I fit my Titan I may need to adjust the steps as the stepper motor is apparently different.
If I were to upgrade to say Marlin, how do I know what needs to be adjusted?

My printer is printing ok and although I would like to tweak it, I don't want to go too far.
Are there no real "instructions for newbies" out there?

A pretty good starting point is Triffid Hunters calibration guide and the G-Code library.

You can find out many of the actual settings by sending "M503" from a terminal window ( Pronterface, Repetier Host, etc... ). The controller answers with a list of the current settings stored in Eeprom. It's worth to copy this answer in a text file for later reference.
All the parameters you see there are editable without reflashing the firmware.
Example:
Your extruder steps/mm are now M92 X??? Y??? Z??? E82.
From the terminal program you send "M92 E410" ( = 82*5 ) followed by "M500" ( store new value in Eeprom )

Edited 1 time(s). Last edit at 06/27/2017 03:19AM by o_lampe.

Wow, thanks. That looks like something I can get my teeth into.
Just what I was looking for.

Salve a tutti, ho un problema di firmware: ho scaricato l'ultima versione di MK4duo mail compilatore mi da i seguenti errori
C:\Users\PERSON~1\AppData\Local\Temp\arduino_build_777259\sketch\src\HAL\HAL_DUE\HAL_Due.cpp: In static member function 'static void HAL::analogWrite(pin_t, uint8_t, uint16_t)':

C:\Users\PERSON~1\AppData\Local\Temp\arduino_build_777259\sketch\src\HAL\HAL_DUE\HAL_Due.cpp:520:5: error: 'g_pinStatus' was not declared in this scope

g_pinStatus[pin] = (g_pinStatus[pin] & 0xF0) | PIN_STATUS_PWM;

^

C:\Users\PERSON~1\AppData\Local\Temp\arduino_build_777259\sketch\src\HAL\HAL_DUE\HAL_Due.cpp:520:52: error: 'PIN_STATUS_PWM' was not declared in this scope

g_pinStatus[pin] = (g_pinStatus[pin] & 0xF0) | PIN_STATUS_PWM;

^

C:\Users\PERSON~1\AppData\Local\Temp\arduino_build_777259\sketch\src\HAL\HAL_DUE\HAL_Due.cpp:524:5: error: 'g_pinStatus' was not declared in this scope

g_pinStatus[pin] = (g_pinStatus[pin] & 0xF0) | PIN_STATUS_TIMER;

^

C:\Users\PERSON~1\AppData\Local\Temp\arduino_build_777259\sketch\src\HAL\HAL_DUE\HAL_Due.cpp:524:52: error: 'PIN_STATUS_TIMER' was not declared in this scope

g_pinStatus[pin] = (g_pinStatus[pin] & 0xF0) | PIN_STATUS_TIMER;
exit status 1
Errore durante la compilazione per la scheda Arduino Due (Programming Port).
Non riesco a venirne a capo, inoltre con i movimenti manuali gli spostamenti sono molto limitati rispetto ai comandi impartiti nelle due modalità (coordinaate assolute e relative), ho un bed da 40 x40 cm, cartesiana. help!