In Spanish "ja, je, ji, jo, ju" and "ge, gi" all of them sound like "ch" in German or "x" in Russian. The English word "Loch" took its sound from German, so you can compare. It sounds harder than "h" in English. Though in many Central American countries "j" is pronounced exactly as "h" in English, though that is not the standard pronunciation.
Some words with these sounds are:
Jamás, jerez, jinete, joven, juez, gente, gimnasia.
I hope this helps.