Current exposure to my LEDs

[tooki]

I decided to take BrokenYugo's advice and order one of these: https://www.ebay.com/itm/122604065816
Obviously, I don't know what the hell I'm doing and didn't know which watt to order and didn't know which 'k' value to order. I finally decided to order the 3w with 'cold white' which had the highest number 'k' value.
Would one of you be so kind as to tell me how to power it? I'd like to use USB if possible, but a battery pack would be just fine if that's what I need. And I'd also need some advice on which resistor.
Thank you again for all the explanations.
PS: For the life of me I cannot get my account or profile configured so that I get emailed when someone responds to my posts. I've tried several times but can't get it to work.

FYI, what you’re calling the “‘k’ value” is the color temperature, given in Kelvin (so capital K, not lowercase k which stands for kilo). Higher color temp = more blue, lower color temp = more yellow/orange. Around 4000K is “natural” white, anything much lower is warm white, anything much higher is cool white.