I can't tell if you are using the right terminology. If you are just asking how to tell the tense of a sentence, since Klingon does not conjugate the verb for tense, then you use what we call a "time-stamp". Tense is set by adding information to the sentence or story about when that sentence or story is set. "YESTERDAY he saw a human." "TOMORROW he will see a Ferengi." "NOW he sees Klingons." Sometimes the time-stamp is more complicated like, "When I was a child..." And when telling a story, the time context may be set early in the story and never mentioned again. It's much like in English, when you come across the sentence, "I read a book." If I was already writing about the past, then you will probably pronounce the word "read" as "red". But if I am writing about what I do after dinner, then you will probably pronounce the word "read" as "reed". You can tell from the context whether the word is past or present even though it is spelled exactly the same.
On the other hand, if you really did mean participles, then the answer gets more complicated and I will only give you a very basic preview now, but you will learn more later in the course. Participles can be translated into Klingon using the verb suffix -bogh: laDbogh tlhIngan "A Klingon which reads," or, "A reading Klingon." Again, the tense is context dependent and is not indicated in the verb itself, though aspect (which English speakers combine with tense) is often used on -bogh phrases. Aspect is also discussed in more detail later.