No props at all ? No whiteboard, no flipchart ?
Can only really get up and speak then.
Start with a few sentences of introduction and setting the relationship between you and the audience. Then go into the prepared subject matter.
Can be useful to hold a set of cards with bullet point reminders of what point you wush to civer next so nothing is forgotten and it all comes out in a logical flowing order.
Have a sort of conclusion/ending, few sentences in mind to finish up with.
Take a few deep breaths before you start, try to treat it a little different to speaking to a few friends, and any nerves should diminish.
Just one thing to watch. Check how fast you're talking, it can be easy to get faster and faster if inexperienced. Spotting if this is occurring and slowing down helps both calming yourself and making for a better presentation.
Good luck.