This question arose today, when used this for the first time. Manual states only, that the robot gets the money before starting to build his cities, however:
1. If this robot is - no doubts about it - we bid immediately, winner places first city since the robot is fort to place cities.
2. If this robot is not the :
A) we bid first, then earlier players places cities, then the robot
B) we bid just before the robot's turn
Today we played variant B, however this might be very strategic decision, especially, if the robot has high value power plant... In our case, my wife started with her cities and afterwards had only 1e, so I won the bid with 2e and made the robot block her effectively. If we played the variant A, she might have at least risen the bid, so my advantage is not that much significant.
Combined with "buy all cities" it might be even effective to bid all your money left, so the robots buy significant number of cities next to your opponents, slowing them down a lot.
We coincidentally had that robot the last time we played a few nights ago.
We understood it to mean: at the time of the robot's turn to build his first city, we humans then bid for the right to say where the robot would build his first city. (So your option 2B.)