You need to be in week 2(i think) to even start her stuff,
You need to deam about her twice,
It's more complicated if you don't have the lucky perk which you can simply add with the Cheat menu,
Then you need to progress Sam till she introduces you,
Which is after the wedding (Marriage Sucks event) where you hang out with her and bake something,
The following being the sex at home event which changes how Sam introduces MC to Emma you should do Emma before this as to avoid beating around bushes,
So after Marriage Sucks go to the bakery and meet Emma,
Then you gotta get Sam to arrange a date,
After the date you gotta meet Emma a few more times before starting to date her to which you never insist on hot coffee,
Eventually she'll start the fun stuff,
Last I played she was incomplete.