Pumping ?? Please help.

De
I'm currently EBF my LO ( almost 3 weeks old) and I want to start pumping and start a stash. I'm not too sure where to start. I would like to start with 1-2 pumping sessions a day, when would be the best times to do that? How long should I pump for? 
Any tips and tricks of the trade would be very much appreciated!! 😛