There might be some slight variations in sequence depending on the specific airplane’s automatics/certification, but the basic idea regarding commercial jetliners is to first get maximum weight on the wheels, since most (almost all) of the braking action comes from there. Once reverse thrust has spooled up, it may be quite ineffective anyway due to being at low speed already.
Therefore:
1. Stop the acceleration (close thrust levers)
2. Start wheelbraking and get weight on the wheels simultameously (brakes, speedbrakes)
3. Initiate reverse thrust
But then again, airlines differ in their utilization of automatics...
My personal view: If aborting (something serious wrong already), I wouldn’t rely too much on auto-features.
happy landings
dolly