If your total expenses are less than your total income, you can use the surplus to prioritise paying off debts or put it towards your savings or investments.
But if your total expenses are more than your total income, you'll have less money at the end of the month than at the start. If that's the case, you should focus on ways to reduce your spending before you save on a regular basis.
If total expenses are higher than your total income, you might want to look at ways to reduce your spending and set yourself a budget. Perhaps you could:
Since circumstances may differ for everyone, there's no specific amount you should save each month. Your assessment of your expenses and income will help you determine how much you can afford to put aside.
Some people find it helpful to follow the 50-30-20 model. That means you aim to spend no more than 50% of your total income on the things you need, 30% on the things you want, and set aside 20% to build up your savings or repay debts.