The new motherboard will of course come with a box and manual. The pin configuration and pictures are inside the manual. The connectors from your casing will be separated by color wires, some 2-pins, some 3-pins, some multi-pins like USB 2.0 or USB 3.0 front panel connectors. The connector housing will have labels like "HD Audio" to let you know what they are. Then follow the pin configuration on the motherboard manual.
I know people think it is cool to throw away the user manuals. But when you need it, you should refer to it. It's faster than waiting for forum answers who don't have your manual. You have it on your hands, refer to it.