You have set a target of 3 months. Identify what you want to learn in 3 months. This could mean learning enough to greet people, ask for directions, order food, etc. Learning everything that there is to know about the German language in a span of mere three months is a much-desired idea, but impossible to achieve. You are a curious student who is entirely new to the German language.
The German language is wonderful to learn, full of grammatical rules that are simple to understand and words that are easy to remember and pronounce. Like learning any other language, you must hear it, write it, read it, and interact in it. What you hear, write, read at the elementary stage is important because it instills either a love or a fear of the subject. Moreover, it should be at your place of understanding. This will help you to become familiar with it and feed it into your mind in small pieces.
In 3 months, you will surely learn some basic vocabulary and the method of using it to form coherent sentences. To become comfortable in speaking, at the beginning, you will need a capable partner who is encouraging, patient, who speaks slowly, clearly, and gently corrects you as you learn to speak.
If you are passionate about learning or possess a flair for languages, you would be able to master more vocabulary than is usually expected in a short time.
There are various methods, tricks, and apps that help you to remember words and rules. You can set targets for yourself, such as learning a fixed number of words per week and forming simple sentences with your vocabulary. For example, 10 words per week. Identify what it takes for you to learn it well, with minimal effort. This could mean learning with a group of friends, solo, classroom, or experiential learning.
Of course, having the right teacher will make all the difference. Apps are a wonderful idea to learn faster, very useful for learning the language easily. It is so wonderful to learn new languages. Go and check it. Best website and apps for learning German.