Decide which style of street dance you would like to learn. There is a large variety of street dance styles, so start with one that you like to watch. To give some examples, there is hip-hop, break dancing, popping, and locking. There are also many different styles that originated in different cities, such as krumping, which originated in Los Angeles but has become popular worldwide. Watch videos online of each style and decide which one appeals to you.
Find teaching videos in the style you have chosen. You can find the video doing a search using the title of the dance. Watch through them until you find one that appeals to you, and with a teacher whose teaching style you feel works for you. Make sure they walk you through the steps slowly and give clear explanations of the movement.
Clear a space on the floor near the computer where you can follow along with the instruction. Make sure you are wearing comfortable clothing that allows you to move easily and tennis shoes which are typically used in street dancing.
Watch the first step on the video more than once to get a good idea of what the step should look like. Listen to what the instructor tells you.
Follow along as the instructor walks you through the first step on the video. Rewind the video if you need to do this more than once. Stop the video once you feel like you have the step, and practice it a few times on your own. Once you feel you have a handle on the first step, restart the video and go through the same process with the second step.