I'm less dismissive of the book idea than some of you. 18 months ago I found myself jobsearching for the first time in 30 years and it soon became very apparent I needed to master Twitter quickly.
I went to my local library (we still have a few that haven't been closed) and browsed the computer, jobsearch and business shelves. Found three books that looked at Twitter from different perspectives. All helpful.
Yes, it's designed to be easily accessible but some of us like to learn in a reflective rather than active, trial and error, style.
So, my advice for what it's worth is your local library if accessible. Otherwise the local adult ed classes as already suggested. Look for the half day, taster style classes.
I work for a charity for older people and we run such tasters so depending on your age this too is an option.
Good luck. I will say I find Twitter increasingly addictive, so beware too!