# Building a 4 - bit adder: 0. To save the simulation press `ctrl + s` or click `Simulation` > `Save`. Save your progress after each step. 1. Create a new ic called `half-adder` (`Create simulation` > `Integrated circuit` > `Half adder`) 1. Add the following logic gates (`Logic gates` > the name of the gate): - 2 buttons - 2 light bulbs - a XOR gate - an AND gate > You can get more info about these gates by clicking `Logic gates` > the info icon at the rght of the gate. 3. To move a gate, drag & drop it with the right mouse button. To connect 2 pins, click once on each. Build the following configuration:  3. Create a new ic called `full-adder` (See step 1) 4. Add the following gates (See step 2): - 3 buttons - 2 light bulbs - 2 half adders - an OR gate 5) Build the following configuration (See step 3):  6) Create a new project called `4-bit-adder` (`Create simulation` > `Project` > `4-bit-adder`) 7) Add the following components (See step 2): - 8 button - 5 light bulbs - 3 full adders - 1 half adder 8) Build the following configuration (See step 3):  9) Enjoy! Congratiulations! You've made your first circuit! With this simulator at your dispossal, the possibilities are endless! Here are a few things you can try and create yourself: - A 4-bit substractor - A counter - Different latches - If you are confident in you skills, you can even make a full 4-bit processor!