Could someone help me learn how to form plurals in this particular case?

Question

When a noun ends in -ou, I've read that it can be followed by both -s and -x, (des bisous, des bijoux) so, how can you know if it should be -s or -x ?

Accepted Answer

Bonjour Tibor,
That's a very interesting question. Most nouns will take an -s in the plural form. However there are exceptions are you've mentioned. 
Take a look at these 2 links:
Most nouns take an -s in the plural unless they already end in -s, -x, -z (the second video in particular - 7 exceptions)
French Plural 
I hope this is useful.
Bonne journée !

Answer

Hi Tibor,I think the following link may help you:-https://www.lawlessfrench.com/grammar/nouns/Bonne continuation.Jim