Sequence of stages (high level)

Matching: Intended parent(s) identify a gestational carrier, either independently or through a surrogacy agency.
Legal contracts: Both parties (with separate legal counsel) negotiate and execute a Gestational Carrier Agreement (GCA) that defines rights, responsibilities, compensation, and parentage.
Medical preparation: The carrier undergoes medical and psychological screening. The intended parent(s) or donor(s) complete IVF to create embryos.
Embryo transfer: A viable embryo is transferred to the carrier's uterus. This may require multiple attempts.
Pregnancy: The carrier carries the pregnancy with ongoing medical monitoring and communication with the intended parent(s).
Birth: The child is born. In most U.S. states, a Pre-Birth Order (PBO) or Post-Birth Order establishes the intended parent(s) as legal parent(s).
Legal parentage: The birth certificate reflects the intended parent(s). This process varies by jurisdiction.

Roles of each actor

Intended Parent(s): Initiate the process, provide genetic material (or select donors), fund the arrangement, and become the legal parent(s).
Gestational Carrier: Carries the pregnancy. Has no genetic connection to the child. Provides ongoing consent throughout the process.
IVF Clinic: Creates embryos, performs medical screening, and conducts the embryo transfer.
Reproductive Attorneys: Draft the GCA, file for parentage orders, and ensure legal compliance. Each party should have independent counsel.
Agency (if used): Matches intended parents with carriers, coordinates logistics, and manages communication. Not required but common.
Escrow Company: Holds and disburses funds according to the contract terms.

Whether to use an agency or pursue independent matching.
Selection of IVF clinic (which may differ from the clinic the carrier uses for transfer).
Number of embryos to transfer (single vs. multiple).
How to handle pregnancy complications or medical decisions.
Whether to pursue a Pre-Birth Order or Post-Birth Order (jurisdiction-dependent).

Consent in surrogacy is not a one-time event. It is an ongoing process with specific checkpoints:

If consent is withdrawn at any stage, the process stops. Contracts define remedies, but cannot force medical procedures.

Before matching: Attorneys advise on jurisdiction selection and legal risks.
Before contracts: Independent legal counsel reviews terms for both parties.
Before medical: Clinic conducts screening; psychologists evaluate readiness.
Before birth: Attorneys file for Pre-Birth Orders (where available).
After birth: Attorneys finalize parentage and birth certificate.