Try to replace les or leur with names. If there's a preposition in front of them, they are indirect object pronouns and will be replaced with leur. Otherwise it will be les (direct object pronouns)

Je parle à Marie et Sean. --> Je leur parle.
Je suis venu voir Marie et Sean. -- Je suis venu les voir.

Hi Langaj,

We are here to help, but we need to understand exactly what is causing you difficulty?

Perhaps you can give a couple of sentences or other text which you have difficulty with?

Jim