We do not use the present simple to talk about activities we are doing right now. For that, we use the present progressive. The present simple (also called simple present and present tense) is used to talk about:
things that are facts (The earth is round.)
general truths (Restaurants serve food.)
regular activities (I take a shower every day.)
When the subject is he, she, it, or a name
For regular verbs, add an s at the end of the base verb.
I love ice cream.
He loves ice cream.
Paul loves ice cream.
For verbs that end in sh, ch, s, z, x, or o, add es at the end of the main verb.
I wash dishes every day.
My mom washes dishes every day.
For verbs that end in consonant + y, change the y to an i and add es.
I carry my purse everywhere.
She carries her purse everywhere.
For irregular verbs in the present tense
Modal verbs and the verbs be and have do not follow these rules.
Do not add an s to the end of modal verbs.
I can play the guitar.
He can play the guitar.
For the verbs be and do, there are no rules regarding the ending.
I am a business woman.
You are a business woman.
She is a business woman.
I have a good job.
He has a good job.
Forming the negative
Use verb + not for the auxiliary verb be.
I am not sleepy.
You are not hungry.
He is not here yet.
Use do not (don't) or does not (doesn't) to form the negative version of the present tense.
I don't love ice cream.
He doesn't love ice cream.
Paul doesn't love ice cream.