This page allows you to set the physical limits of the axis drawn in the display area. The default configuration auto-scales all spectra to fit within the currently available display area.
If you want to apply limits of your own then, untick the auto-scale checkboxes and enter your values in the lower and upper entry areas. Remember to press Draw to apply the limits.
You can also get either axis to display itself using logarithmic scaling (if possible, there are limitations, like not being able to contain the coordinate zero) and to display the axes ranges flipped top to bottom or left to right.
Other useful options are the checkboxes Fit X range: and Fit Y range: that also make the ranges that you supply fit the visible display area exactly (these are like the fitwidth and fitheight options in the plot window) and Y auto cut: which applies limits to the Y axis using percentile cuts.
The Update to current button sets the X and Y limits to those of the full plot (these are the values shown initially). The Update from view button sets the X and Y limits to those of the visible part of the display area. This is useful to just show coordinate axes for what you can see.