1) If you go on a steep slope you have to be prepared to take many falls.
2) If you go on a steep slope you have to be ready to take many falls.
1) & 2) "急斜面に行くなら、たくさん転ぶのを覚悟しないとだめだよ" という意味です.
急斜面に行くなら:If you go on a steep slope.
たくさん転ぶのを覚悟しないとだめだよ:you have to be ready/prepared to take many falls.
Be prepared to take many falls if you're going on the steeper slopes.
"Be prepared to take many falls if you're going on the steeper slopes."
「もっと急な斜面に行くのなら、たくさん転ぶ覚悟をしておいて」
* be prepared to: 覚悟しておく、用意をしておく
* take a fall: 転ぶ → take many falls の複数形で「何度も」転ぶ
* if: もし
* go: 行く
* steeper slopes: より急な斜面
ご参考になれば幸いです。