Why is navigation not showing in vuepress?

Question

Vue.js

Hello!
config.js:

module.exports = {
    locales: {
        '/': {
            lang: 'ru',
            title: 'название',
            description: 'описание',
        }

    },
    themeConfig: {
        '/': {
            nav: [
                {text: 'Главная', link: '/'},
                {text: 'Второй раздел', link: '/public/second/'},
                {text: 'Третий', link: '/public/third/'},
                {text: 'Ещё один', link: '/public/fourth/'}
            ]
        }
    }
}