When working with larger models you probably will reach a point when the model becomes too large to fit on the page. You can change the scale of an individual Assembly on a page by right-clicking the Assembly image and choose Change Scale from the pop-up:
The default Model Size 1,000000 is 100%. You can type in a new value or use the small arrow buttons to decrease the scale. Of course you can also increase the scale. Click OK when done.
Finally then you are given the choice of changing only the current step or not:
Obviously you should choose Yes here, since the scale of previous assemblies can stay as they are. Choosing No will result in rescaling all assemblies. Would this be necessary it is better to change the Global Scale settings for scale.