1. GO = Eu uso para falar que eu planejo ir a algum lugar no futuro. Exemplo: I go to supermarket tomorrow. No, this isn't correct. You don't use this form for future plans - for future plans you say 'I'm going to the supermarket tomorrow' or 'I'm going to visit London next month' or 'I'm going to study French next year'. You use the form 'go' (or 'play' or 'speak' or any other verb) for general facts and regular habits in the present. 'I go to the supermarket every day' 'I play football every Saturday' 'I live in Brazil'. This is the present simple. 2. GOING = Eu uso para falar que eu já estou a caminho de algum lugar, que eu já estou ANDANDO a caminho de algum lugar, em movimento. Exemplo: I am going to the supermarket. This is correct. This is the present progressive form, and we use this to say what we are doing at the moment. 'I am studying English' 'I am sitting by my computer' 3.GOING TO = Eu posso usar o TO após o GOING para informar a direção Exemplo: I am going to the soccer this time (I am going to the soccer match at the moment). Yes, this is a present progressive, and it's the same as number 2 - this is what you are doing at the moment. ou falar de uma ação no futuro proximo. I am going to fix your problem. Yes, this is the same as the example I gave you for number 1 (I'm going to visit London next month/ I'm going to study French next year).