The simple present is used mainly for mentioning actions in present but in a simple way, basically it is necessary to define who makes the action (subject), the action (verb) and the complement (object). there are two auxiliar verbs that when those are auxiliar verbs they lose their puctual meaning. those are DO and DOES, And their use depends on the pronoun.
I You We They He She It
Its structures are:
(+) suj + verb + compl
(-) suj + aux. verb + not + verb + compl
(?) Aux, verb + Suj + verb + compl ?
(+) You read a book
(-) You do not (don't) read a book
(?) Do you read a book?
*in negative, the suggestion is to use the auxiliar verb and the negation by themselves (do not) but depending on your own decition you can contract the two words (don't)
In this grammar tense there are 4 exceptions that they must be learnt to a proper manage of the foreign language.
1. The final -S: the rule says that all the verbs next to a singular third person pronoun (He, She or It) it must finish with the letter -S, this doesn´t change its meaning, it is just a grammatical rule.
He listens to music
Mary jumps in the bed
2. when the verb finishes with the letters SH, SS, CH. X y Z: the exceptions work only when the main verb in the sentence is next to the pronouns He, She and It. In this case, the verb must finish in -es
she kissES a boy
Pedro watchES the bad movies.
3. When the verb finishes with the letter -O: It works in the same way with the previous exception. If the verb finishes in -O it must finish in -es
The tree doES exercise each monday.
Peppa goES to UK.
4. When the verb finishes with -Y: when the -y is next to a consonant, the "Y" is replaced by -ies, but you have to be careful because if the "Y" is next to a vowel, you only have to put a simple -s