There is a bath inside the building and from there, you can go out to the bath located outside.
The two baths are connected, the one inside and the other outside. You can get to the one outside from the inside one.
ご質問ありがとうございます。
① "There is a bath inside the building and from there,"＝「建物の中にお風呂があり、そこから」
"you can go out to the bath located outside."＝「外にあるお風呂に行ける。」
② "The two baths are connected, the one inside and the other outside.”=「二つのお風呂は繋がっている、内部と外部のが。」
"You can get to the one outside from the inside one."＝「外部のは内部のから行ける。」
ご参考に。
"From the bath inside, you can get to the open-air bath outside."
"From the onsen inside, you can go outside to the open-air onsen."
"From the bath inside, you can get to the open-air bath outside."
"from the bath inside" 「うち風呂から」"from the indoor bath" も言えます。
"you can get to ~" 「〜に行ける」
"the open-air bath" 「露天風呂」
"bath" の代わりに "onsen" も言えます。
"From the onsen inside, you can go outside to the open-air onsen."
"you can go outside" 「外に出られて」"you can go out" も言えます。
"to the ~" 「〜に入る」
アメリカ合衆国 
オーストラリア 
