Centre Line Question

This is a question from a new user who still suffers major hang ups from a life spent in 2D and is still groping his way round inside SolidWorks. Please be kind.

My current problem is I can't figure out how to place to holes in a plane with their centres equidistant either side of the centre of the object they're being placed in. In AutoCAD I'd just draw a centreline and offset the holes from it.

My sort of half learned SolidWorks experience has me thinking i should somehow be creating a relationship to the centre point to set the holes equidistant to it but I can't see how.

Grateful for any guidance

Paul Martin

SolidworksDrawings And Detailing