What should I do for the "s := NewRuleSet ()" structure?

I wrote a structure like this --> https://imgur.com/IULKNol But there are some deficiencies.

So how can i assignment to variable? Or How do I do this? --> https://imgur.com/L9R4KVX Thanks in advance.

Write NewRuleSet so that it returns a struct that you can attach methods to.

your issue is that NewRuleSet does not return a variable

try this

func NewRuleSet() ([]string, []string) {
    return []string{}, []string{}
}

then in your main/test function
func main() {
    depp, conf := NewRuleSet()
}

in Go, like many other languages, you need to explicitly declare what a function returns.
edit:
also, you will need to modify your AddDep and AddConflict to take in the string array as an argument

type RuleSet struct {
   depp []string
   conf []string
}
func NewRuleSet() *RuleSet {
   return &RuleSet{[]string{}, []string{}}
}
func (r *RuleSet) IsCoherent() {
   ...
}