Black boxes problem

I am new to arduino
I am using a arduino mega 2560
and an I2C connected to a 16x2 LCD (1602A)
and all i get is black boxes after uploading the Hello World .
How to fix this please help.

Try adjusting the contrast knob on the display.

I've been trying everything for 5 days i am new to arduino maybe i am sure i have done something wrong with my codes . if you can send me codes compatible with arduino mega 2560 and I2C 16x2 lcd step by step including everything i should do with my Arduino ide software

how to write anything on this plz help with everything
you have to tell me everything i have to fo it is my new day with arduino

boogeyman:
I've been trying everything for 5 days

But did you try what I told you to do?

boogeyman:
plz

Don't ever use that word on this forum! This isn't some idiotic text message. We're discussing complex concepts here that require a your brain to be fully activated. You will write out the full and correct words and use proper punctuation and grammar or you won't be taken seriously.

boogeyman:
you have to tell me everything

No, I don't have to do anything. I'm here trying to help people out as a hobby, not a job. When they start getting demanding and wanting everything spoonfed to them that's when I unsubscribe from the thread and move on to the next one.

well i am only asking for someone that can help me start using ny i2c lcd 16x2 with arduino mega 2560 that is all and yes i have tried adjusting the potentiometer .and i still get black squares .

boogeyman:
well i am only asking for someone that can help me start using ny i2c lcd 16x2 with arduino mega 2560 that is all and yes i have tried adjusting the potentiometer .and i still get black squares .

What operating system are you using?
Which version of the Arduino IDE are you using?
Can you post a photograph of your arduino and the lcd circuit so that we may see what you have wired up?

Details matter. And you have provided very few (not enough).

how many black boxes? 16 or 32? it makes a BIG difference as to what the issue might be.

You also never said which library you are using.

--- bill