By the way, do you still remember what eat and go mean? Yes. They mean ～をたべる and ～にいく.
Today, let's study how to say ate and went. You say たべました（たべます+～しました） and いきました（いきます+～しました).
Present Tense たべます→Past Tense たべました
Present Tense いきます→Past Tense いきました
How about future tense?
Actually, future tense is the same as the present tense. So, it's going to be いきます and たべます but they should be with future indicators such as today and tomorrow.
You say きょう（today）りんごをたべます or あした(tomorrow)バナナをたべません. As far as you indicate whether it's about future tense with those, we can tell it's future tense.