The Legends set is given away during the tutorial of Star Wars Card Trader, starting with Yoda. You’ll get additional cards each day as inserts in your free starter packs. However, when the free packs end, you may find yourself asking…
How do I get Legends Han, R2-D2, and Darth Maul?
Unfortunately, these cards have been bugged since the end of 2015, and are not being given to new players. You’ll have to trade for them if you want to complete the set, and it will be difficult, because most existing copies are in the hands of people who only have one copy themselves and have a complete set that they don’t want to split apart.
Although it was meant to be a part of tutorial, this is now a goal that will take more time. We can only hope that Topps resolves it soon.