How to make my telegram bot to send messages to different chats?

Question

I created my telegram bot which should send every 15 minutes a message. Now it works with my own chat, because i writed my bot to start spam:

let job0
let job15
let job30
let job45

// Command to start scheduler.
bot.onText(/\/start_spam/, async message => {
    try{
        // Starts every 0 minute of hour.
        job0 = schedule.scheduleJob('0 * * * *', async function(){
            await bot.sendMessage(message.chat.id, spam_text).then()
        });
        // Starts every 15 minute of hour.
        job15 = schedule.scheduleJob('15 * * * *', async function(){
            await bot.sendMessage(message.chat.id, spam_text).then()
        });
        // Starts every 30 minute of hour.
        job30 = schedule.scheduleJob('30 * * * *', async function(){
            await bot.sendMessage(message.chat.id, spam_text).then()
        });
        // Starts every 45 minute of hour.
        job45 = schedule.scheduleJob('45 * * * *', async function(){
            await bot.sendMessage(message.chat.id, spam_text).then()
        });
    }catch (error){
        console.log(error)
    }
})

// Command to stop scheduler.
bot.onText(/\/stop_spam/, async message => {
    try{
        if (job0) {
            await job0.cancel()
        } else  if (job15){
            await job15.cancel()
        } else  if (job30){
            await job30.cancel()
        } else  if (job45){
            await job45.cancel()
        }
    }catch (error){
        console.log(error)
    }
});

Now i need this functional: I make command 'start_spam' and it writes not to me, but to some telegram group chat, how can i get this chat id or how to do it in another way?