Dear Ivana,
Here's some information you will find useful in building the Basic Color Instrument. While littleBits are easy to use, making your own at home is an advanced topic! At the forums there are other like minded people who like to make their own bits and try new things, so you will find yourself at home.
1) Wiring and assembly guide from Adafruit.
Replace the blue Arduino with the littleBits Arduino. They even show you how to solder male header pins to the Adafruit color sensor.
2) You can see in the video of this project how I soldered the male header pins to the extra pinholes on the littleBits Arduino. Just like with the color sensor, I used a breadboard to keep the header pins stationary. http://littlebits.cc/projects/animated-grasshopper-jumping
3) A discussion on the forums about how to find and solder wires to the SDA and SCL. You can see there are options, depending on people's supplies and preferences. I chose to cut and strip one end of a female to female jumper wire and solder to these points with no resistors. I recommend these wires be at least 6 inches long. All the wires I used for the color sensor have female ends.
4) A diagram of the littleBits Arduino module with all the pinholes identified. See where there are six pinholes marked "ICSP"?
LittleBits ICSP:
...............................GND --> O O <-- RESET
Digital Pin 16 / MOSI --> O O <-- Digital Pin 15 / SCK
.................................VCC --> O O <-- Digital Pin 14 / MISO
Find a discussion on this topic here: Using the Additional I/Os on the Arduino Bit
5) Another project that uses the color sensor, the Ocular Keytar:

Thanks for visiting the forums, Ivana! Please post your questions and updates with pictures and videos here. Others will learn from your process of discovery! 
-Jude