Hi Prema, this is a wonderful opportunity for you to overcome your fears; don't worry about anything. Just prepare yourself to the fullest.
Preparation for the Speech
Get the summary of the trainers (educational qualifications, achievements, highlights, etc.). Prepare the welcome speech and keep it handy with you on a piece of paper. Learn all the details of the trainers about whom you will be speaking by heart.
Delivery Tips
On the day of the speech, speak to the crowd as if you are speaking among a social circle, but make sure you are professional and polite. Convey the information about the trainers as if you knew them. Speak from the heart, appreciate the achievements as you truly would. Maintain eye contact in all directions slowly and steadily. Never let go of the smile on your face. Keep the welcome speech short.
Handling Nervousness
If you are really nervous, you can use the mic podium. Stand behind the podium and speak, carrying the speech paper with you. If you can't use the podium, then get yourself very familiar with the stage from which you will speak. Go on the platform and rehearse the speech and style again and again; you will start to gain confidence.
Be excited about it; don't fear it. Public speaking requires great effort, and the audience respects those who speak. So don't worry, even if you goof up, it's just a funny incident in your life worth remembering.
Regards