There are a number of ways to split a project. Here is one, which will split your work into three :26 chunks, in this example. Or create smaller chunks...
First, for protection, Save Project File AS routinely, giving it a unique # or name, so as not to overwrite prior saves. Using Save Project Files (no AS) will overwrite. From the HOME tab, that choice is available by clicking the chevron to the right of the Save Project button on the toolbar.
With the scrubber (red line) at the head of the project, place the mouse pointer on the line, hold down the left button and swipe right up to about 26:05. That area turns blue.
Right-click in the blue area and Export Selected Region. This will be your segment #1... 
Do the same for each segment, overlapping slightly with the prior segments, so nothing will be missed. Later, when assembling the segments for final export, you can trim excess duplication at the join points.
This will take some practice. But if you have backed up the initial, full project, you should be good. If you make a mistake along the way, press <ctrl-Z> to backtrack, step-by-step.