Tenses Rules
Simple past tense
Use only the 2nd form of the verb
eg  He wrote a letter
Simple present tense
use the first form of the verb
use s/es with the first form of  the verb
when the subject is singular we use s/es with the verb
when the subject is plural we do not use s/es with the verb
Simple future Tense

we use will/shall with the first form of the verb