There are various resources that can help you organize and format your thesis.
1. UCSD provides documentation for preparing graduate theses and dissertations which may help -- see especially Section III: Organization of Doctoral Dissertations and Master's Theses is probably most helpful, but this also provides very specific detail about specific sections (ie abstracts, acknowledgments, the use of images and statistics, etc.) -- not so much the overall structure and not specific to undergrads.
2. Looking at completed UCSD Theses and Dissertations can also be helpful:
3. There are also additional resources to find undergraduate theses:
Assistance with Writing at UCSD Library
The Writing + Critial Expression Hub offers assistance with: