Get value from a map[string]map[string]interface{} in Golang

Question

I have this structure in golang:

type ScanView struct {
    FileInput       []ScanInput  `json:"inputs"`
    Report          RegulaReport `json:"report"`
}

type FileInput struct {
    Filepath  string                            `json:"filepath"`
    Resources map[string]map[string]interface{} `json:"resources"`
}

I need to assign values to the map depending on the key, I'm doing something like this:

for i, r := range output.Inputs {
        if filepath.IsAbs(r.Filepath) {
            relPath, err := filepath.Rel(inputDir, r.Filepath)
            if err != nil {
                return "", fmt.Errorf("some error log")
            }
            output.Inputs[i].Resources["_source_location"]["path"] = relPath  -> here I need to assign the value for the _source_location key
            output.Inputs[i].Resources["_filepath"][""] = relPath  -> here I need to assign the value for the _filepath key
            
        }
    }

No pretty sure how can I achieve that for a map[string]map[string]interface{} in Golang. Thanks!