I am a bit confused about when exactly to use "le" and "y" to replace it

Question

For example what is the difference or the correct one to say: "J'y crois" or "Je le crois" or "j'en crois"

Answer

Hi Adora,
Yes, it can be confusing knowing when to use adverbial pronouns y and en.  The cases are covered in detail here:
https://french.kwiziq.com/revision/glossary/pronoun-type/adverbial-pronouns 
You can add any of these lessons to your notebook if you want to practise them together.
Hope that helps!

Answer

Thanks!

Answer

I am still confused as to why it's je le crois and Not j'y pense or j'y crois. The first example. Je veux venir à..... i thought you replace with "y" when there is a verb followed by à??? Apologies if this answered elsewhere but the separate lessons don't help make the distinction for me between use of "le" and either "y" or "en".

Thanks if you can help. Ann