You can connect your Arduino board to a computer using a USB cable. To do this, simply plug one end of the USB cable into the Arduino board, and the other end into an available USB port on your computer. You may need to install drivers for your specific Arduino board. Once the drivers are installed, the Arduino board should be recognized by your computer.
You can then write code for your Arduino board using the Arduino IDE software, which can be downloaded for free from the Arduino website. Once your code is written, you can upload it to the Arduino board by clicking the “Upload” button in the Arduino IDE.