I went - Simple Past tense - indicates one or more completed actions in the past
I had gone - Past Perfect tense - describes an action completed before something else in the pastI go - Simple Present tense - indicates a single action repeated (e.g. I go to school every day)
I have gone - Present Perfect tense - indicates a simple action taken at a time before now (e.g. I have gone to the doctor)
I will go - Simple Future tense - indicates an intention (e.g. I will go to the library this afternoon) or a prediction (e.g. the sun will rise in the morning)
I will have gone - Future Perfect tense - indicates an action completed before something else in the future (e.g. I will have learned some maths after my next year at school is finished.)
If you only need to communicate, English is one of the easiest languages to do it in. On the other hand, it is a very difficult language to learn to use correctly - and many of the English themselves have not been taught to do it well. Also, pronunciation is a minefield . . . 
