Welcome to the Apple community and congratulations on your new Mac.
Ok, I would consider a protective case/cover for it see amazon.com, or retailers near you to see what may meet your needs.
You should consider external storage for regular backups and a bootable clone. See https://discussions.apple.com/thread/4099894?answerId=18893335022#18893335022 for information about backing up with a mac.
You may want an external monitor/keyboard/mouse. You should visit your country's apple store/website for details.
You may also want a carrying case/bag for when you're on the go. I suggest you visit a retailer in person with your mac and test out the options they have so you can see what you like best.
For programs consider the "iwork" suite of applications as apple's equivalent of "office". Microsoft does offer a version of office for mac.
Apple has a basic "switch" guide located http://www.apple.com/support/switch101/
There are also other resources for "mac os x for windows users" Search on your favorite search engine for more information.
I hope this is helpful and again, welcome!