What order should i watch Re: Zero in? I don't wanna watch it out of order.

So me and my Younger brother started Re: Zero Starting life in another world. And we did not know which series was season 1. Please help us. I do not wanna skip ahead any parts of the series. So what order should we watch it in? Me and my younger brother enjoyed what we saw so far though. Thanks for the help in advance. Also Twin maids are super kawaii cute. ;)