Arduino IDE
You can get the IDE from the Arduino website.
The Arduino IDE is what you'll be using to write your code, upload it, and interact with the Arduino when it's running.
It looks like this.
Click the tick/arrow in the top left to verify/upload your code (or ctrl+U).
It's good practice to remember the folder your code is saved in so you can put custom libraries in there.
When you upload your code for the first time, it might not work. Make sure the Arduino is plugged in and set the COM port (Tools > Port). You might need to try a few till you find the right one. Make sure the board is correct as well (probably should be Arduino/Genuino Uno).
To communicate to/from an Arduino, you typically use "serial". When you call Serial.println("stuff"); in the Arduino, you can see this on your laptop using the serial monitor (ctrl+shift+M), and also write things to send to the Arduino.