The NVC will send your case to the embassy in your country. Meanwhile the only thing you can do is WAIT.
Once the embassy receives the package, they will send you what is called Package 3 with all the details to continue the process. This package 3 usually involves documents such as DS160, police record, Affidavit of support, birthday certificate... If you want you can start getting the docs in advance, there is no harm in it. But you will receive the official list of documents with Package 3.
Payment of fees instructions are in the package 3 (it is something like 250€). Medical exam is done before your interview (after receiving package 4, also about 200€).
Each country is different so I recommend you to wait and follow the instructions from the embassy letter.
Good luck
I received RFE letter on Monday as well . They requested me documents from the marriage date to the present day . I sent them a box of documents yesterday to keep them busy for a little while .
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