A) Select the language. Ideally, it should be a language which will have some form of relevance in your life - You need to practice it in some way or another. Join an online forum, look for people who speak it around you and try to connect with them, do something which will force you to use it. And it has to be ONE language.

Let me repeat - O.N.E. language.

B) Duolingo. WAIT - Before everyone jumps on me telling me how bad it is - I know. This is just step 2 (or B) and it's meant to help you grasp the very basics with the ability of hearing the pronunciation. You want to learn present tense, past tense, future tense and present continuous.

You don't need to know every single word in the dictionary, just understand the basic grammatical syntax for those 4 tenses and know some basic verbs.

C) Narrate your life out loud. After you wake up, start telling yourself out loud what you are doing. When thinking of what you will do next say out loud what you will do. At the end of the day, recap your day in past tense.

Obviously, you will not know every single verb for every action you're taking throughout the day - You will google it everytime you need to. A dictionary works too, but the idea is for you to start googling it one, two, three, four times until it sticks. You will start building your lexical up from here.

Eventually you will start recognizing patterns in the language, and by speaking it out loud all the time you will get comfortable with the pronunciation faster.

D) Once you're comfortable enough with narrating your whole day a few days in a row without needing to google too much, move on to learning present perfect and past participle, alongside the grammatical syntax for questions. (Duolingo, once again).

Introduce them into your narrations somehow.

E) Remember I said the language you picked had to be relevant in your life somehow? This step is why - Practice it. Start using it in real life for whatever you planned to use it. You already know the basics and got enough to communicate with someone else. So just get used to it.