What is the order for watching Lupin III?
Different to a lot of other anime franchises, almost all stories in Lupin are independent of the others so there is no required viewing order to understand them. All you really need to know is who the characters are.

But if you want to have some hints for watching the tv series, take a look at this. And if you are interested in the movies, specials and OVAs, take a look here.