It depends on what effect you want. You can talk about the past in past tense because it happened in the past, and you can switch to present tense when you're not longer talking about the past. Or, if you want to make it seem more like a story, you can talk about it in the present tense from the POV when it was happening to you.
I walked into the bar to get a drink 5 years ago.
As I was walking into the bar, I had an overwhelming desire to get a drink.
It just depends on what effect you want.