だけで

A noun or verb + だけで can be used to express that just having X or just doing X is fine. It's often translated as "just by [verb]" or "just with [noun]."

日本に行ったら、英語は使わないでなるべく日本語だけで生活するつもりだ。
When I go to Japan, I plan to not use English and to live just using Japanese as much as possible.

この植木は２週間に一度水をやるだけでいいですよ。世話が簡単です。
This plant just needs to be watered once every two weeks. It's easy to care for.

スミスさんは自分で勉強しただけで、日本語が話せるようになりました。
Smith-san studied all on his own, and he got to where he could speak Japanese.

お金を入れてボタンを押すだけで、暖かいラーメンが出てくる自動販売機がある。
It's a vending machine where just by inserting money and pressing a button, you get warm ramen.