The Spherical Tokamak for Energy Production (STEP) aims to build a fusion power plant (SPP) that can generate energy through nuclear fusion. The SPP's plasma creates extreme heat, particle, and structural loads on the plasma-facing components (PFCs) of the divertor, limiters, and first wall. These PFCs must manage heat and particle loads, as well as safety, net power generation, tritium breeding, and plant availability. To identify suitable PFC concepts, an iterative design methodology called 'Decide & Iterate' has been used to synchronize decisions within the fast-paced design process. The 'Decide & Iterate' methodology involves four decision sets. Decision Set 1 focuses on PFC wall shaping, heat load zoning, and limiter positions. Decision Set 2 addresses integration with the wider system, including the outboard first wall (OFW) and breeding zone. Decision Set 3 involves technologies, coolants, and materials, considering neutron effects and material degradation. Decision Set 4 deals with coolant service routing and structural support, ensuring compatibility with plant-level requirements. Key PFC solutions include a helium-cooled discrete and panel limiter design to enhance tritium breeding and allow individual limiter replacement. The OFW is integrated with the breeding zone to improve fuel self-sufficiency and power generation. Heavy water (D₂O) is used in the inboard first wall and divertor PFCs to increase tritium breeding in the outboard breeding zone. The inboard first wall (IFW) uses water-cooled PFCs with D₂O to improve shielding and tritium breeding. The methodology enables the identification of PFC concepts that meet the SPP's requirements, including managing heat and particle loads, ensuring plant availability, and supporting tritium breeding. The 'Decide & Iterate' approach allows for rapid iteration and adjustment of designs based on plant-level requirements. The final design includes full-height tile-on-heat-sink PFCs for the IFW, which reduce part counts and complexity. The methodology also addresses challenges in coolant service routing and structural support, ensuring the SPP can meet its functional and performance requirements. The PFC designs are crucial for the success of the STEP programme and may be applicable to other fusion machines.The Spherical Tokamak for Energy Production (STEP) aims to build a fusion power plant (SPP) that can generate energy through nuclear fusion. The SPP's plasma creates extreme heat, particle, and structural loads on the plasma-facing components (PFCs) of the divertor, limiters, and first wall. These PFCs must manage heat and particle loads, as well as safety, net power generation, tritium breeding, and plant availability. To identify suitable PFC concepts, an iterative design methodology called 'Decide & Iterate' has been used to synchronize decisions within the fast-paced design process. The 'Decide & Iterate' methodology involves four decision sets. Decision Set 1 focuses on PFC wall shaping, heat load zoning, and limiter positions. Decision Set 2 addresses integration with the wider system, including the outboard first wall (OFW) and breeding zone. Decision Set 3 involves technologies, coolants, and materials, considering neutron effects and material degradation. Decision Set 4 deals with coolant service routing and structural support, ensuring compatibility with plant-level requirements. Key PFC solutions include a helium-cooled discrete and panel limiter design to enhance tritium breeding and allow individual limiter replacement. The OFW is integrated with the breeding zone to improve fuel self-sufficiency and power generation. Heavy water (D₂O) is used in the inboard first wall and divertor PFCs to increase tritium breeding in the outboard breeding zone. The inboard first wall (IFW) uses water-cooled PFCs with D₂O to improve shielding and tritium breeding. The methodology enables the identification of PFC concepts that meet the SPP's requirements, including managing heat and particle loads, ensuring plant availability, and supporting tritium breeding. The 'Decide & Iterate' approach allows for rapid iteration and adjustment of designs based on plant-level requirements. The final design includes full-height tile-on-heat-sink PFCs for the IFW, which reduce part counts and complexity. The methodology also addresses challenges in coolant service routing and structural support, ensuring the SPP can meet its functional and performance requirements. The PFC designs are crucial for the success of the STEP programme and may be applicable to other fusion machines.