You cannot directly transfer your Help to Buy ISA into a Tembo Lifetime ISA.
If you no longer want your money in your Help to Buy ISA, you can manually withdraw your savings and deposit them into your Lifetime ISA with us at Tembo, via direct debit or as a one-off contribution from your connected bank account.
Before transferring, check with your current provider on any rules or government conditions around withdrawal.
Remember: that you can only deposit up to £4,000 each tax year into a Lifetime ISA, so if you've got more than this in your Help to Buy ISA, you'll need to split it over multiple tax years.