How to add up qada prayer and perform

Assalamu walaikum,I've been searching for a answer for my question,Due to laziness i failed to pray 3 prayers (yesterday 2, today's 1) ,so i want to pray the Isha prayer,but the thing is, I'm confused,cause,I also had many qada prayer from before(I made a list of which day and which prayer I didn't prayed),so if i pray isha, should i pray the missed 3 prayers first ,or can i add this 3 prayers to my qada prayers list and then pray at a comfortable schedule