Gem4me vacancy

fullstack-vacancy.ts

const responsibilities = [
    'Chat-bots and theirs environment',
    'Different backend tasks',
];

const needToKnow = [
    { languages: ['JavaScript', 'TypeScript'] }, // ES6, Node.js, TypeScript - strong knowledge
    { frameworks: ['Express.js', 'Koa.js', 'Hapi.js'] }, // preferred to know Express.js and Koa.js
    { databases: ['Relational', 'NoSQL'] },
];

const niceToKnow = [
    { environments: ['Linux'] },
    { tools: ['CI/CD'] },
    { containers: ['Docker', 'Kubernetes'] },  // one of them
    { cloud: ['Amazon WS', 'Microsoft Azure', 'Google Cloud Platform'] }, // one of them
    { testing: ['Mocha', 'Chai', 'Jest'] }, // one of them
];

class JsFullStackDeveloperVacancy extends Bot {
    @ReadMore('https://gem4me.com/ru', 'About project')
    public project: Project = Project.Gem4Me;

    public async onMessage(message: Message, candidate: Candidate) {
        switch (message.command) {
            case '/what_you_will_do':
                return `You will help me with: ${Object.keys(responsibilities).join(',')}`;

            case '/what_i_need_to_know':
                return `We are working with: ${Object.keys(needToKnow).join(',')}`;

            case '/what_are_nice_to_know':
                return `It's very nice to know: ${Object.keys(niceToKnow).join(',')}`;

            case '/im_ready_whats_next':
                return await this.wantToWorkHard(candidate);

            case '/im_part_of_the_amazing_team':
                return `${this.project}: Welcome bro!`;
        }
    }

    public async wantToWorkHard(candidate: Candidate): Promise<boolean> {
        // TODO: Check if candidate want to be part of amazing team
    }
}

This is a great format, but

"You will help me with: 0,1"
"We are working with: 0,1,2"
"It's very nice to know: 0,1,2,3,4"

what does this mean?