A plate member for a cell stack, a cell stack assembly, a method of forming a plate member for a cell stack and a method of assembling a cell stack may be provided, and the plate member comprises a channel sheet comprising at least one peak and one trough for forming fluid flow channels; two alignment parts, each alignment part comprising a main body and one or more alignment members, the main body having a through hole provided within the main body; and wherein the alignment part is capable of aligning the channel sheet parallel to a plane of the main body and the alignment member is capable of aligning the alignment member to another corresponding alignment member along an axis passing through the alignment member; and further wherein the channel sheet is disposed between the two alignment parts.