What an introduction from the gents!
As they said, I'm a proud and happy double bagger. In fact, today is exactly 1 year from my surgery.
Always happy to answer specific questions, but some basic advice:
Read up in advance. It won't all stick, but whatever you remember, you won't have to learn the hard way.
Check out the UOAA website.
It will be overwhelming at first. This is probably true for everyone with even 1 stoma. But I think it is worse for those with 2 new stomas at once. There will be a learning curve in the beginning, and you will naturally make mistakes and have accidents. With 2 stomas, this happens twice as often. It's like a crash course. On the plus side, you will end up learning from mistakes with 1 stoma and not make that same mistake with the other. So you'll get through the overwhelming period twice as fast.
Make sure you have services from an ostomy nurse for after you go home, whether this is through home health care, a clinic, or a combination. You will have problems, questions, and need advice that is best delivered by a professional who can see your exact situation.
See an ostomy nurse to mark your stoma placement in advance of surgery. You want flat areas of the abdomen, away from scars, the belly button, skin folds, and bend locations.
Get some incontinence pads to place on furniture and your bed. They make disposable ones, but I bought fabric ones that can be laundered and reused off Amazon. The fabric is more comfortable and more environmentally friendly. Accidents will happen, and these provide a lot of peace of mind. I have only needed these a couple of times early on, but what a relief not to be damaging my bed or upholstered furniture when things go wrong.
Plan to get a hernia support belt. You'll likely need to get this custom made, which takes a really long time (about 2 months). Ask your ostomy nurse for suggestions, but I've only found 2 places that will do 2-bag belts.
Nu-Hope, you can get instructions from their website; you send the tracing to them, and they create a template. They will call with the template number. Then you order through your medical supply company.
Www.ostomybagholder.com
This is a direct order site with measuring instructions online.
Stealth Belt used to do these, but they've undergone some management changes, and I don't think they do them anymore. Ostomy Bagholder is similar in style.
Last but not least, keep coming back here. You'll learn a ton from other ostomates. 1 baggers only have one stoma to worry about, but the problems are the same. There are few things that are specific to a particular type of ostomy and even fewer specific to 2 baggers. We can all learn from each other.