Chinese is a very difficult language and for a tourist, it is not realistic to become proficient in a month. You should focus on learning some basic phrases that will allow you to communicate in common situations where English is not spoken. In large cities at places like airports, high-end hotels, museums and common tourist places, there are a lot of people who speak English. However, throughout most of China, English is not widely spoken. In general, people will like you more if you show them you have made an effort to learn their language and culture. There are around 300 languages spoken in China, but Mandarin is by far the largest and most important one to study. Most people speak Mandarin, even if their first language is a regional one, like Cantonese.
To help you learn some basic survival phrases, three resources are highly recommended:
1) https://www.italki.com/ Italki is a website where you can pay native speakers living in China, some of whom are tour guides, to teach you basic conversational Chinese. Prices range from $8 to $20 dollars per hour on average. You can choose someone who lives in the area you will be visiting. They can also give you advice on places to visit, how to get there, and help you with any questions you might have.
2) https://www.mylanguageexchange.com/ Mylanguageexchange is a website that lets you do language exchanges with people in nearly any country. You can connect with people living in China and teach them your language in exchange for free Chinese lessons. Because it is free, this is an obvious advantage for people on a budget, but it is also a great way to make friends and learn much more than just a language. For example, if you are going to Tibet, while most people speak Mandarin, you might want to learn Tibetan. You can learn Tibetan on this website.
3) https://www.youtube.com/@MandarinCorner2/videos Mandarin Corner is an excellent channel on Youtube that provides many videos that teach Chinese speaking, listening comprehension and culture. There are also many other channels on Youtube that offer survival phrases for tourists.