What is PCI Express? Do PCIe lanes, slots, and versions matter?

What is PCI Express? Do PCIe lanes, slots, and versions matter? pcie 3 slot The adapter card I am looking at can be used in a X4, X8 or X16 PCIe slot and they say I will get up to 32Gbps when it is plugged into a PCIe pcie expansion slot Bandwidth of PCIe · PCIe x16 : 128 Gbits · PCIe x1 — open stack: 8 Gbits · PCIe x16 : 32

pcie expansion slot PCIe bifurcation PCI Express bifurcated Riser Card ITX to ATX x4x4x4x4

pcie 4 m2 in pcie 3 slot Bandwidth of PCIe · PCIe x16 : 128 Gbits · PCIe x1 — open stack: 8 Gbits · PCIe x16 : 32 For example, a PCIe x1 slot provides one lane and transmits data at 1 bit per cycle x cards seamlessly plug into PCIe slots, and