First things first, you need to know that if you can fire a rifle or bow, then you can fire a crossbow. If that gives you an idea then the better it is. Meaning it is very simple and straight forward like most firearms. But there are still a few things that you need to know.
You need to know how cocking works. Before you load a crossbow with an arrow, you obviously have to pull the string back on both sides of the barrel consistently and evenly with the right pressure to make sure it is properly aligned. Misaligning the string of the bow as little as 1/8 inch is enough to redirect your arrow’s trajectory several inches from your desired target point. If you cock your bow with your hand, it is the fastest and easiest way to do it but also at the same time difficult. However if you are going to use a cocking rope it makes the string feel more lighter as you pull it and will give you consistent cocking and will reduce the tension of the string as you pull back, also reducing the effort to half. Remember, if you are a vertically challenged person, a cocking rope can be more of a hassle than a help to you but no need to worry, there are cocking aids available out there like the crank operated ones and these devices come built in with the bow so you might need to look into that before buying. Although they can be expensive, loud and sometimes slow. But a crank can help you cock your bow even if you are weak.
After cocking you can place a bolt or an arrow on the barrel of the bow, you can see a groove in the barrel that the vane or feather will fit into. Some arrows use moon nocks or flat nocks and it all depends on who the manufacturer is. Now you make sure that the arrow is secure, when everything is ok and it is time to shoot, all the basics of accuracy for a bow or rifle will come into work prior to shooting. Before taking the bow out of safe mode and pulling the trigger, don’t put any part of your body anywhere near the barrel especially your fingers.
If you change your mind before shooting, you can always leave your bow cocked even all day but make sure you remove the arrow from the barrel before you walk around or climbing down a tree. But if you are hunting, you will only un-cock your bow at the end of the hunt. But if the need arises, you can just remove the hunting tip arrow from the barrel and then replace it with a blunt tipped arrow meant for this purpose then aim at a safe target like a soft piece of ground then shoot like normal. The scary stories you hear about bows dry firing, also happens to for crossbows as well, so be careful.