take out the pen refill, remove the spring from the old pen refill, slide the spring over the new pen refill point and place it back into the barrel. screw the bottom tip back into the pen and you are all set! if you are looking for pen refills be sure to get a parker style refill. if you have trouble replacing your ink refill contact me and i will work you though it. if you have trouble finding pen refills, i sell them here as well. 