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/he/she/we/you/they/anybody hit.

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.

 Add 'wud'. 
I hit wud.

Add 'get'. 
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'.

That's it. 

You know everything about every verb.