You have an extra nut and sleeve. They usually include one set with the male fitting, and then both sets with the line when bought separately. First put the male fitting in the block. Personally I'd next just take the nut and sleeve off one end of the line (leave the small insert inside the line) and use the sleeve and nut that came with the male fitting for that engine side of the line (just in case there is some small variances). Or you could also just remove the nut from the male fitting and use what is already on the line if they appear same as what came with the male fitting. Run the other end thru the firewall to your gauge. Can't remember if you have to remove nut or compression sleeve to get it thru the firewall grommet, or if the grommet is split. See AIM UPC U17, sheets A3 and A4. It says to coil any extra length inside the console. Others will chime in if I missed anything. I'd also ensure the line is good and clear before installing, and fully seated into the fittings before tightening the nuts.