what is it like being a sailor?为当个水手如何,请问being 怎么理解,是like do

是 be 的进行式没错,句中的 it 就是 being a sailor 的代名词.
原句可以写成：What is being a sailor like?
当、做、成为、作为 这些意思都可以用 be 的各种形式来表达,比如：
What would you like to be when you grow up?你长大后想做什么（工作/从事什么职业）?
She has been （完成时）a teacher for 3 years.她当老师已经3年了.
Being a famous writer,what would you recommend?作为一个知名作家,您有什么建议?
这句 what is it like being a XXX 的句型就是在问对方,作为一个 XXX 是什么样的感觉?