Typing crontab -e I get a screen full of lines beginning ~. I can type a cron command and there is a line "I /tmp/crontab.BRW2C3 [Modified] 2/2 100%" at the bottom of the screen. However, I don't recognise the editor so don't know how to save it.
I'm used to Ubuntu, where there are a lot of comments at the beginning of the file and nano/pico is the default editor.