This is what in some languages like Spanish is referred to as direct pronoun. So if you are doing something that affects directly somebody or something you add את (which sounds like ET) before the noun or the person that is being affected by the action. In this case somebody is drinking something, so the action is drinking. You can ask what are you drinking, and the answer is the juice. So the juice is the direct object that is being affected by the action. This is why we had the word את.
Another example is "I open the letter". If you translate this sentence to Hebrew you would say "I open ET the letter" (אני פותח את המכתב)
Hope now it's more understood
Not sure what you're asking. I've downloaded Hebrew as another keyboard language (Win/Space to switch). I then typed the keys into a text document, which I refer to whenever I have to write in Hebrew. I open it on a second screen so I can refer to it as I type.
Hope that's what you were asking.