Use an ejuice calculator like ejuice me up. Without knowing the percentages of flavoring and your vg/pg ratio, I cannot give you the percentage of nic to add.
Dude, no offence here but as someone who is obviously starting out on the whole diy journey i would really really recommend you wear gloves at the very least. 60mg/ml nic is not really for beginners. Be very very very careful please.