There are two ways to change sounds, quick & easy, or one that means you need to learn some fighter factory code. The quick & easy one is "I dont like that sound I wish it was this sound instead" then you just go into FF, find the sound, and there's a replace button right there to put the sound in you want. BUT if you want to add new sounds and have them play where you want and not replace old sounds, it is more complicated.
You have to add the new sounds and make sure you are not replacing other groups or indexes. It helps to reuse groups, like if lewd sounds are in 2008 group starting at index 0 and the character has 5 lewd sounds, they will be like 2008,0 - 2008,4, then you can make new lewd sounds and start them at 2008,5 or whatever second number you want as long as it doesn't replace the old ones. After that, you will want to look up tutorials on "PlaySnd" in the States tab bc its very hard to understand by just reading my dumb posts.
long story short regular edit tutorials arent any different than NSFW, youre doing the same things, just one is lewd and one prbly isnt