My husband has a European birth certificate that had to be specially translated. We had a situation where we had to actually order all of these things twice. I almost could not get copies of my birth certificate again and I had to do crazy deals and pay a lot of money for it. Take the most important things at the top which must be done now and descend down to lesser matters. Keep this list, a yellow legal pad is great, check things off but keep it visible so you can see what you did and what you need, etc.
Listing also works great when getting ready to plan and pack for the trip.
If I did not keep these things in labeled files, upright and safe, I would have lost my mind entirely. There was no way I could do this with mess and chaos. Think of it as your huge college project or something. If you are adopting with a partner, split up the tasks what suits your personalities best, work together when you can and drink a lot of coffee, ha ha. If one of you is better on the phone or better at organizing, you know who has to do what.