To change margins in Microsoft Word, check out this link: Change the margins in your Word document - Microsoft Support. Be sure that your work has 1” margins (1.25" allowed on the top and bottom), and that all figures, tables, etc. fit within these margins.
Please look at Insert a section break - Microsoft Support. Keep in mind that section breaks are useful for formatting and layout purposes, such as creating different page orientations or header/footer for different sections of your document.
Yes, see how to use both landscape and portrait orientation in the same document: Video: Use landscape and portrait in the same document - Microsoft Support
This tutorial below will be helpful to look at how to insert landscape page numbers in Microsoft Word: Microsoft Word Landscape Page Numbers - YouTube. This video was created by the Mississippi State University Graduate Council.
This video (created by North Carolina A&T Graduate College) shows you how to manually create leader lines for a Table of Contents:
Leader lines (Thesis/Dissertation Formatting) - YouTube
This is a tutorial created by Dr. James Clark (King's College London) that shows you how to set up Headings and automatic tables of contents for Scientific reports and documents: Microsoft Word - Heading formatting and table of contents - YouTube ©2013 James Clark, king's College London.
You can find the entire set of tutorial videos here: https://ehealth.kcl.ac.uk/sites/physiology/LST-MSOffice5.html