Hello again! Could, should, would are all the conditional tenses and in Dutch this is formed by taking the auxiliary verb ''zullen'' and placing it in the past tense, together with the infinitive of what it is you want to express. I'll show you the conjugation so you know how it goes.
Present tense
Ik zal
Jij zal/zult. Zul je? (When inversed)
Hij zal
Wij zullen
Past tense
Ik zou
Jij zou
Hij zou
Wij zouden
With the present tense of zullen, you can make the future tense. And with the past tense you form the conditional tense.
Could: zouden + kunnen
Should: zouden + moeten
Would: zouden
So, here you have some examples!
I will be able to help = Ik zal kunnen helpen
I could/ would be able to = Ik zou kunnen
We could sleep for a bit = we zouden even kunnen slapen
He will go = Hij zal gaan
He would go = Hij zou gaan
You should go = jij zou moeten gaan
You would go = jij zou gaan
They wouldn't do it = ze zouden het niet doen
You will go = jij zal gaan
I should go = Ik zou moeten gaan
We should eat = we zouden moeten eten
We will eat = we zullen eten
we will have to eat = we zullen moeten eten
Let me know if this answer is sufficient for you! :)