Say our new language has a verb 'hit'.
You can guess what it means.
This one invariable word - & I want to stress that absolutely ALL words should be invariable – will be the infinitive.
It will also be the present tense, for any & every subject.
I didn't mention the invariable word order: subject-verb-object.
To make a past tense, just add the invariable word 'did' after the infinitive.
I hit did.
She hit did.
Note that, in general, all qualifying words should come after what they qualify, unlike in English.
To make a future tense, add the invariable word 'wil' after the infinitive.
I hit wil.
You hit wil.
I hit wud.
You hit get.
Combinations of passive & others are possible & obvious.
He hit get did.
You hit get wil.
Most languages have lots of additional tenses & moods.
Subjunctives, imperfects, continuous…
They certainly add possibilities for subtlety & refinement.
I think a basic language can & should manage without.
In the interest of simplicity, above all.
So, in summary:
To learn any verb, you just learn one word, which stays invariable.
For every verb:
Future – add 'wil'.
Past – add 'did'.
Conditional – add 'wud'.
Passive – add 'get'.
You know everything about every verb.