Over Constraint in Sketch

I'm having an issue with the 2D sketch. No matter how many times I redo the sketch and follow the instructions, after I trim the bolt hole offsets and dimension the outer circle to try to fully define it (lost once bolt hole offsets were trimmed). It comes up as 'over constraint' I did manage to get this to work once but then once I used the fillet tool the same issue arose when trying to redefine the outer circle. Please help! I'm at a loss of what to do, tried redoing multiple times to no avail. Thanks :)

This example is turning into a bit of a fiddly one that's causing some confusion. I'd love to re-do when I get the chance.

That said I do still think it's a good example to illustrate the main points.

What I will say is don't focus too much on trying to follow every mouse click exactly and try to understand what's really going on, what's causing any issues and what needs to be done to fully constrain the sketch.

The "over constraint" warning will pop up if you try to control something that's already controlled - For example dimension the diameter of a circle that has an equal constraint to another circle that has the diameter already controlled by a dimension. These relationships can get quite complicated quickly though.

I always recommend clicking and dragging the unconstrained parts of sketches to see how they move. This will show you exactly what constraints or dimensions are needed to lock them down.