That is false. These are not verbs, there is no present, past or future tense for these.
Ott -> there
oda -> to there
Ott vagyok -> I am there
Ott voltam -> I was there
Oda megyek -> I go there
Oda mentem -> I went there
I can think of many situations. I can be there in my imagination, I can be there tomorrow, I can be (there) where we first met, etc. It is either that Iam not actually there, or I am saying it from the other person's point of view.
Some speakers would normally say "Here I am". At least where I am in America, that kind of wording is usually archaic and we'd say "I'm there". Maybe if I were playing hide and seek or peek a boo I'd say "Here I am", but I can't think of many other scenarios.
The only situation I can think of is when you're on the phone or Skypeing someone form another country. You tell them to look at a map and once they see that small country beside the bigger one, you can say "I'm there."
When you are looking at a picture / video and spot yourself, you could say that "I am there". During a phone conversation when you are following instructions to "go to X street" then you would say "I am there". So... it depends on the context.