How do I know it's Braxton Hicks?

Sa

Almost every evening after diner, my belly feels hard and sometimes uncomfortable.

It last it lasts more or less 10 minutes 'till 30 minutes. When I relax, it goes away.

I guess it is not braxton hicks, because they happen less than a minute, am I right?

Other than that: how do I recognise braxton hicks?

Thanks in advance!