Yes, I attend local events for the Deaf in my community.
Your fear of communicating with a deafblind person is completely normal and understandable.
To initiate communication with me, touch my hand. At that point, I will place my hands over yours so you can begin signing.
There are many other ways deafblind people communicate including FM system, tactile/visual sign, TeleBraille (Braille TTY), Teletouch (a device that looks like a typewriter and has a QWERTY keyboard on one side and a single Braille display on the other...when a key is depressed on the QWERTY keynoard, it appears on the Braille display), large print TTY, CART (computer assisted real-time captioning), Screen Braille Communicator (similar to the Teletouch in that it consists of a QWERTY keyboard on one side, a Perkins (Braille) keyboard on the other and either a 1 or 8 cell Braille display as well as a print LCD screen), Braille/raised print alphabet card, fingerbraille (tapping Braille letters and numbers onto one's lap, arm, or back using the first 3 fingers of each hand) and print on palm (tracing block print in the palm of one's hand).
Communication with a deafblind person:
If you don't know how much a deafblind person can see, it is best to move in front of them, touch their arm gently and move back a little further to sign slowly in a fixed range at the level of their vision. If you don't get any response, gently touch their hand.
If you already know a person is totally deafblind, always touch their hand to get their attention.
Many deafblind people have some residual hearing and/or vision. Only 3% of the deafblind population is totally deaf and blind.
Here's a website which explains how to communicate with the deafblind:
Tips On How To Communicate And Comply Effectively with A Deaf-Blind Person.
I hope this information helps! If you have any other questions, please feel free to ask!