Help! 30 hour childcare and tax free childcare

They are different things.

The 30 hours are for working parents, with certain restrictions on income, and can be used at registered providers to offset the cost. Most nurseries also charge fees on top for consumables ie food, nappies, formula etc. They are only available during term time ie 38 weeks of the year, so some nurseries also offer them spread over the full calendar year so your 30 hours turns into about 22 hours a week if spread.

The tax free childcare is essentially like a bank account, and again has certain restrictions re income. Once set up you pay money in, and for every £8 you pay in the government tops up £2 (up to a max of £500 every 3 months). You then pay your nursery direct from this government account. For example your nursery bill could be £600 a month but you pay in £480 the gov tops up £120 and then you pay the £600 total to your nursery.