Once Goldra1n detects the device in DFU mode, click the "Start Exploit" button. You will see a terminal-style output scroll across the tool's window. The limera1n exploit is being sent via USB.
What happens next?
Goldra1n specifically targets devices with the Apple A4 chip. If you own an iPhone 4 (GSM or CDMA), iPad 1, or iPod Touch 4G, this is the most reliable tethered/bootrom jailbreak available for Windows. It allows you to dump SHSH blobs directly from the device without relying on Apple's defunct signing servers.
Warning: Jailbreaking may void any remaining warranty (unlikely on vintage devices) and can expose your device to security risks. Proceed only if you understand the risks.