Please use the format below if you find it helpful. I guess that you would be giving a 10/15 minute presentation, and my suggested content for it would be as follows if you were doing an engineering masters degree project:
1. Define or explain the problem you were looking at or trying to solve.
2. What has been done in that area of study and/or current trend.
3. How did you go about it solving it, eg. lab experiment including equipment, experimental method/s and technique/s used, etc.
3.1. The data collected including theoretical calculation.
3.2. Analytical method used.
4. Result including accounting for uncertainties such as the effect of parameters that may have influence the output of the data collected from your labwork or experiment.
5. Proposals for future work. Always remember that your work is only a part of a bigger picture.
The above are what I believe that you should be able to clearly explain in your viva because they are part of the work you have or should have done.
I wish you all the best and I pray for you that God grant you wisdom and all forms of strength to successfully complete your viva in Jesus's name, amen!
Be blessed and don't get stressed out.