I think this is a basic but a tricky question.
I'm not a teacher, but please let me try to explain this to you.
As for conjugations of verbs in Japanese, we have only two forms, a dictionary form and ta-form.
(Sometimes a dictionary form is called non-past form (非過去形（ひかこけい））, whereas ta-form is called past form(過去形）.
You will be able to understand if you read further.)
Ta-form means for past tense.
A dictionary form of action verbs such as よむ, たべる, いく, のむ, means future tense,
whereas a dictionary form of static verbs such as いる, ある, means present tense.
◎an action verb ending sentence
・future tense: use dictionary form
(I will read books.)
#2 カフェで コーヒーを のむ／のみます
(I will drink a coffee at a cafe.)
・present tense: use て-form of an action verb + いる／います
(I read books.)
カフェで コーヒーを のんでいる／のんでいます
There is an exception.
When a dictionary form goes with a phrase expressing something habitual, the sentence becomes present tense.
#1' （わたしは）『まいにち』ほんを よむ／よみます
(I read books every day.)
#2' カフェで 『まいあさ』 コーヒーを のむ／のみます
(I drink coffee at a cafe every morning.)
◎As for a static verb ending sentence (including an adjective ending sentence),
a dictionary form means present.
If it's necessary to make it future, just add a phrase expressing future.
(I feel somehow that we rarely use future tense for these sentences though.)
・present:がっこうに せんせいが います
( Teachers are at school.)
・future:らいげつには ここに あたらしい せんせいが います
( A new teacher will be here next month.)
I hope I won't make you confused.