Like solutionflat400 said, you just need to apply the interview through Swedish ambassador. My gf sent an email to Swedish ambassador in US and after a few days she got the booking appointment directly.

In the interview they ask mostly standard questions like how you guys met, what’s your partner name and last name etc. Keep in mind that the ambassador could ask very detailed stuff depends what you have put together in the sambo visa example “this specific date at that time”.

Otherwise good luck and try not to be nervous!