How to put nikon d3100 pics on computer?

I just bought a nikon d3100 slr camera and have already taken a lot of pictures. Now i want to put them on the computer but there was nothing to plug the camera into the computer in the camera box. Do i have to purchase something separately or is there some other way to put them on the computer? Please help, i need to clear my camera's memory by friday to take pictures at a family event. Thanks so much, and serious answers please! I will vote for a best answer!

Nikon D3100

Interface: USB 2.0 (High-speed), Video output, HDMI output (Type C mini-pin connector)

Connect it with USB cable to your computer.

Most of us regulars here use and recommend usb card readers for upload because they work, very well. I've been using readers for years. They're not expensive and are available where ever cameras are sold.