Age 75 and know nothing about investing

We have saved for retirement but have stayed out of the stock market because of ignorance/fear - you name it. I figure if I don'tunderstand it, I shouldn't be in it. But have had most of our money in CDs for past year or two. Those high rates are going to go away soon, and wonder if someone can suggest 2 or three relatively safe (as in, we won't lose money if possible) ETF's to put our $ in that may generate some income for the next 20 years..... thanks in advance and please, no lectures.