How to Quickly Center Multiple Bodies Along the center of a Surface

I’m currently working on a 3D model and need to align multiple blue bodies so that they are centered along the middle axis of a surface. There are four blue bodies, and they need to maintain a fixed interval of 40mm between them. Does anyone have any tips or methods to achieve this quickly and accurately?thx

a) Center along middle axis - This is best achieved by sketching, selecting the center point and drawing a rectangle, which it looks like you have already done.
b) 40mm fixed intervals - Select your blue body and use the Pattern tool, simply type in quantity 4 and spacing 40mm.