>>44688373
If you mean (You)rself, you can raise Cooking and Singing by assigning Food Cart/Restaurant jobs to yourself and having (You)rself do Concert. (You) can be assigned to any of the basic jobs, including the Brothel even if you are a totally inexperienced virgin FeMC.
As for everyone else, it depends - Non-Combatant characters can be assigned to the Restaurant job, unless they are non-cooperative (because you Trained them prior to a Fall). Depending on their initial talents and experience, they may also qualify for the Concert job. For combat-able characters, including Demons, they must have a Fall state first. Any combat-able character can work in the Restaurant if they have the required points, which is a total of 6 points from (Servicing + Obedience + Cooking). If they have Affection Fall state, they only require 3 points, and if Love Fall state, 0 points. Getting Affection Fall state automatically qualifies someone to work in the Restaurant pretty much, as even with Untrained Fall activated, getting Affection Fall through this way automatically gives them Obedience 3.
Concert work requires the character to have a Fall state regardless first, and then needs to meet the points requirement. It's a bit more complicated, so refer to here:
https://wiki.eragames.rip/index.php/EraMegaten/Concert
Note that if you have Untrained Trust Fall on, that actually makes them able to do Concert stuff much sooner since Trust Fall contributes to the points. It's designed this way because attempting to Train a Trust Fall character causes them to lose the Trust Fall, even if you immediately End Training without doing anything, and cause them to become non-cooperative. Note that if they have both Trust and Affection Fall from Untrained Fall, Trust Fall goes away but Affection Fall remains - they won't become non-cooperative because of this but because they lose the bonus points from Trust Fall, you can suddenly have an idol who's no longer qualified to work as an idol anymore until you get other things up to reach the required points again.