Technically speaking, the ~て verbs are not in a "tense": the て ending is a conjunctive or connective form, basically meaning that the action of the verb happens, and then the next thing happens. The て ending itself suggests that the action of the verb completes (technically a kind of grammatical aspect), but it doesn't tell us anything about when the action takes place (what tense tells us) -- it could be in the past, right now, or in the future.
Read through the Wikipedia links above, those will help you get a better handle on aspect and tense. Then, if you still have questions, please either update your question here, or post a new question.