The recommended pinout for the 6-pin UPDI connector is shown in AVR UPDI Pinout.
Connection to a 6-pin 100-mil UPDI Header
Use the AVR 6-pin adapter board to connect to a standard 100-mil UPDI header.
Connection to a 6-pin 50-mil UPDI Header
Use the AVR 6-pin mini adapter board to connect to a standard 50-mil UPDI header.