How do I bulk up? -bad appetite-?

long story short i am 178cm and weigh 54kg which is soooooo low. red zone kinda low.
i need to bulk up and be at least 60kg thing is I don't know how. my appetite is so picky and i barely eat anything because of that.

so any advice you got i will take it.

*i tried going to a nutritionist he gave me cortisone filled drug which is dangerous and has too many side effects.
How do I bulk up? -bad appetite-?
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