I was a little surprised when I first saw this question, because based on my limited knowledge, "h" is always silent in Roman languages, such as French, Spanish, Italian, and Portuguese. (Well, someone might argue that, for instance, French has silent and aspirated "h", but "h" is still considered silent/mute in terms of pronunciation.) Therefore, comparing a silent letter with a sounded letter is honestly somehow strange.
If you were talking about the pronunciation of the two alphabets in Spanish, i.e., "g [xe]" and "h [atʃe]", I believe that you are able to search for any videos from youtube for references. Otherwise, I guess that you were instead talking about the pronunciation differences between "g" and "j [xota]" in Spanish. In this case, I would say that "j" is always pronounced as [x] regardless the following vowel, while "g" is pronounced as [g] (strong sound) when followed by "a, o, u" and as [x] (weak sound) when followed by "e, i". [This is something similar to English, but English is far worse because it is also influenced by German, where "g" is always a strong sound regardless the following vowel. This is why there are words like "get" vs. "gel", and "gift" vs. "giant", where strong and weak "g" sounds are fully mixed up.]
In case that I misunderstood your intention of this question, please kindly further explain it on the supplementary section, and I shall try my best to help.
---
Good day. / Que tengas buenos días. / 좋은 하루.