urgent nursing advice needed

I have just brought my dad home from hospital, he has a broken femur which has a pin in it. We have to administer an injection every day which I have been shown, but I'm not very confident first time. Someone has kindly offered to collect medicines for me and I would really appreciate a helping hand to show me how to do the first injection.
I live opposite the new La Marina Market (Chinese shop). If anyone is willing to help can you contact me via here.
Thanks in advance.