How do I make a drawing bigger not just scaling

I have a drawing of a 3d printer everything is to proper scale but instead of the printer being 200mm x 200mm x 150mm I would like to make one side from 200 to 300. I have tried to scale but
it wont chance the whole drawing or when it does it distorts it all. Do I just re draw everything?

It would be easier to understand the situation that you try to describe if you illustrate it with a screenshot.

From what I can guess, you want to change the overall dimensions of the model without stretching it. Scaling does what is says, it scales everything in an object according to the scale factor. How would you want SketchUp to know what to scale and what to keep?

So you have to tell SketchUp more about how you want this operation to be done (what to scale, what not). So you have to do it using a more differentiating approach.

For this purpose, the move tool is more appropriate. Carefully select one half of the model (all objects that should not be stretched) and move it to the target position.
Faces of which you moved an edge would extend automatically. Depending on how the model is structured, you may have to select some components and scale/stretch them.

Okay have a simular problem need to make this Lens.skp just 5 mm bigger in diameter ! . . Making things in Sketchup Make on a laptop and using the touch pad to adjust things is fun hahaha What kind of a mouse do you suggest to use for these fine adjustments
lens.stl (23.2 KB)

If you want help with your SketchUp model, upload the SKP file, not the STL.

Just get a basic 3-button mouse.