'I’d' is a contraction for either 'I would' or 'I had'; the way to distinguish them apart is that 'would' is always followed by a base form verb and 'had', as an auxiliary verb, is followed by a past participle.
eg: I'd show them. 'show' is the base form so it means 'I would show them'.
I'd shown them. 'Shown' is the Past Participle so it means 'I had shown them'.