From the official policy
"The foundation is laid with strict guidelines in the players’ own homes. They must always consider their own health, therefore showing responsibility for their team and all people. Crowds of people are to be avoided, they are to stay at home and in their own family. Just as millions of people are currently doing, they should pay attention to common hygiene measures."
More can be found here:
https://www.bundesliga.com/en/bundesliga/news/hygiene-concept-explained-dfl-taskforce-season-restart-coronavirus-11150
It should be noted that the policy was developed before the re-start. Since last weekend, the restrictions have been relaxed a bit. E.g., the substitute players on the bench do not have to wear masks anymore, as long as they practice social distancing. There is even talk about having some fans in the stadium for the German Cup final at the end of June. I do not know if the relaxation of the restrictions also addresses the social life of the players and coaches.
Interestingly, some players see it as advantage to play in an empty stadium. Joshua Kimmich (Bayern Munich, German National Team): “The positive thing is you can speak to everybody and maybe the focus is more on the game. It’s not like a show.”