It is probably most convenient to write up your lab reports as Maple worksheets. To do this, you need to know how to insert text blocks in a worksheet. By default, a Maple worksheet only has input and output regions. You can change an input region to a text region by placing the cursor in the input region, clicking on the Input region and selecting Text from the menu that pops up. This changes the input region into a text region where you can type any text you want.
To end a text region and start a new input region, go to the Edit menu and select the Insert Separator Line item to insert a separator line (if desired). Then choose Insert Prompt from the Edit menu to begin the new input region.
The Edit menu has several other entries that you can use to format your worksheet. You can also control the fonts Maple uses for input, output, and text regions from the Options menu.