The first step in a CPU instruction cycle is

The instruction cycle is the sequence the CPU repeats to process every program instruction. It consists of four stages in a fixed order: the instruction is first retrieved from memory, then decoded to determine what operation it represents, then any required data is obtained, and finally the operation is carried out.

The very first stage, in which the CPU retrieves the instruction from main memory and places it into the instruction register, is called fetching. Nothing else in the cycle can happen until the instruction itself has been brought into the processor, so fetch must always come before decoding or execution.

A common mix-up is placing decoding before fetching, but the CPU cannot decode an instruction it has not yet retrieved. Remember the cycle order as fetch, decode, execute (with any needed data access happening as part of execution) to avoid this error.