I would suggest you ask your instructor for more specific direction regarding what s/he wants included in the lab report.
If you are to compare and contrast the similarities and differences in structure between plant and animal cells, you need to describe what you observed and draw conclusions. This could involved describing how you made slides for your observations, the types of dyes you might have used to bring out structural features, other tests you did to observe how the cells react to specific chemicals - these could be considered methods used in your research, and may need to be included in your report. You may also need or want to include illustrations of the different types of cells with the parts labeled, with or without description of the function of each part included with the label or in your report.
Or, your report may be intended strictly to describe experimental activities carried out using both animal and plant cells. If you created and tested a hypothesis regarding how the cells would react in a certain situation, your lab report should focus on describing the method you followed, the results you observed, and the conclusions you reached.