There is too much info to post on this subject. Go to tackleunderground and read all the safety precautions on pouring lead in the wire bait section. My biggest concern for you depending how old you are is getting burned versus lead poisoning.
Here are some pointers:
#1. Don't smoke, eat or drink when you are pouring lead
#2. Pour in a well ventilated area.
#3 Do not pour in the house, preferably in the garage
#4 Make sure you wear, eye protection, face shield, long sleeve shirt, long pants, shoes and socks, even in summer time
#5 Pay attention to what you are doing and make sure you have no distraction when you are pouring ( ie kids and pets running around)
#6 When you are done pouring, wash your hands several times in cold water.
Above all lead is very hot, don't get burned, because if you do it is serious.
Your dad has every right to be concerned for your safety, if that is you in your avatar, you seem like a young guy, stay safe and take every precaution, so your dad can see that you are responsible.
We were all young once and wanted to do things. I am not concerned for you about lead poisoning as much as getting burned, as younger people have a tendency to want to hurry and get things finished so they can do other things. Take your time and think things through thoroughly. Plan everything you are going to do, so you don't make any serious mistakes.
If you have any questions ask first to get all the facts before you attempt this. If you want you can PM me or I can call you to help you with any questions.
There are many other things that will come along the way but I stress safety as #1.