How to use 'have had' and 'had had'

Some English lessons for you people! The BBC Learning English website teaches us how to use 'have had' and 'had had' together in a sentence. From BBC:

Had had is the past perfect form of have when it is used as a main verb to describe our experiences and actions. We use the past perfect when we are talking about the past and want to refer back to an earlier past time, Madiini. In these examples, note the use of before, after, already and by the time as a trigger for the past perfect. Note also that the contracted form of had had is 'd had.

-She'd had a lot to drink and wasn't capable of walking home by herself.

-After he'd had a good night's sleep, he felt much better.

-She sacked him before he had had a chance to explain his behaviour.

-By the time he was twenty he'd already had four different jobs.

-I'd already had a word with Joan about re-locating to Manchester and now she's had time to think about it, she quite likes the idea.

Ah, now I know.