The Supreme Court did not decide if DACA is lawful or a good policy. The decision is limited to "whether the agency complied with the procedural requirement that it provide a reasoned explanation for its action." How and if DHS chooses to proceed in the future (i.e., retaining DACA, issuing a new memorandum/explanation ending DACA, etc.) remains to be seen.
The Supreme Court's decision means that DACA should be fully reinstated, allowing for first time DACA requests. With that said, DHS will need to reopen the DACA policy for new requests consistent with today's decision. However, this may not happen immediately.
The Supreme Court's conclusion that DACA was terminated unlawfully means that advance parole should be reinstated. DHS will need to reopen the DACA policy for advance parole requests consistent with today's decision. However, this may not happen immediately.
Yes. If you have been granted DACA before, you should be able to submit an application to renew DACA.