Holy moly. Twins!
Ok so advice:
1. Have a room that either of your can sleep in for an hour that doesn't have babies in it.
2. Download a couple of engaging mobile phone games and podcasts. Your downtime is important, but alot of it will now coincide with holding a tired baby. So plan for something you can do from the armchair in the babies room for a bit of escapism.
3. Buy your partner 60 minutes peace each day by taking the kids out for a walk without her. Women can experience a crushing pressure from the dependance, and having some time where they can still feel like themselves is huge.
4. With twins, it may be 6 months before your next shag. Prepare yourself, and try to be understanding.
5. BUY SHIT SECOND HAND ON FACEBOOK MARKETPLACE OR GUMTREE. Anything to improve your situation, just buy it.
6. Twins will pay dividends down the line. They'll be great playmates, which will make your life easier.