When you use a telescope for your stargazing, it usually comes with a finderscope, a small attachment which allows you to focus on the correct part of the sky. To align your finderscope and telescope:
Get your alignment target in the centre of the field of view of your main scope.
Your scope may have come with a cross-hair attachment that you can fit to your eyepiece to help you get the target exactly in the centre.
Adjust your finderscope using the small screws attached to it, so that your target is exactly in the centre of your crosshairs.
Keep rechecking and adjusting until you’re sure your finderscope and telescope are looking in the same direction.
Your telescope and finderscope will be aligned. This means that when you’re stargazing at night, you can use your finderscope to track things down and be confident that your target will be in view in your main scope, too.