FR: ça / cela / ceci / ce - place comme COD

[Whodunit]

Can somebody explain to me where to pose the demonstrative pronouns ça/cela/ceci/ce?

Are they to pose in the same way like the direct pronouns "le, la, les" ?

1st E.g. "Je déteste ça" or "Je ça déteste" or "Je le déteste" ?

2nd E.g. "Je suis aussi d'avis que il te faille faire ça !" = plus bref: "Je suis aussi pour ça" Is it correct?

If you don't know what I mean, I'll try it English:

What is "I hate it" in French?

What is "I'm of the opinion that you have to do that!" in French. I.e. briefly: "I agree!" And what is that in French?

Please help me! --> I'm so desperate!!!

 

[OlivierG]

Can somebody explain to me where to pose the demonstrative pronouns ça/cela/ceci/ce?
Are they to pose in the same way like the direct pronouns "le, la, les" ?

No, they don't. "ça, cela and ceci" have to be written at the position of the complete object they represent:
"Je vais remplir le sceau"
-> "Je vais remplir ceci"
but
-> "Je vais le remplir"

For "ce", as a demonstrative pronoun, it can only be used as a subject, not as a direct complement.

"Un petit coup sur les doigts n'est pas douloureux"
-> "Ce n'est pas douloureux"

1st E.g. "Je déteste ça" or "Je ça déteste" or "Je le déteste" ?

It is "Je déteste ça" and "Je le déteste".
Note almost all your sentences are colloquial, because "ça" is a colloquial way for "cela".

2nd E.g. "Je suis aussi d'avis que il te faille faire ça !" = plus bref: "Je suis aussi pour ça" Is it correct?

Almost.
"Je suis aussi d'avis qu'il te faille faire ça"
"Je suis d'accord avec ça"

If you don't know what I mean, I'll try it English:
What is "I hate it" in French?

"Je déteste ça" or, more formal, "Je déteste cela".

What is "I'm of the opinion that you have to do that!" in French.

"Je pense que tu dois faire cela" or "Je pense que tu dois le faire"

I.e. briefly: "I agree!" And what is that in French?

"Je suis d'accord".

 

[Whodunit]

Thank you very much. And thanks for your examples ...
I'm writing a colloquial text. That's why I used ça instead of cela.

[…]