Many community groups either coordinate or support forums, workshops or conferences. There are some very useful tools available via Drive to assist your group with these.
Like any major activity, planning and organisation are critical to the success of an event. Tools available which can assist this include:
Google Sheets is the equivalent of the Microsoft PowerPoint software, with some particular advantages.
Presenters can start a live Q&A session with an audience during a presentation with Google Slides. You can present questions at any time, and people can ask questions from any device.
Instructions on how to enable this are here: https://support.google.com/docs/answer/6386827
This Hints page has a range of tips and hints on effective presentations. It includes a presentation for PowerPoint, and another for Slides.