My screen is cracked and am wondering how to replace it with a new one that I purchased.

If your speakers aren’t playing audio or the audio coming from the speakers is broken or crackling, one of many problems could be the culprit, but there is usually a simple fix. To diagnose and fix these problems, you can follow the Can’t Hear Audio From Chromebook section of the troubleshooting page. The following page is another helpful resource on the topic: How to fix the no sound problem on a Chromebook

If your computer isn't holding a charge your battery is likely just old. Many laptops batteries support around 400 recharges which ends up to be around one or two years, and from then on only hold a fraction of the charge. This is a easy fix though, you should just follow this guide on which battery to get and how to replace it in your computer yourself.

First, there can be issues with debris cluttering the keyboard. If the debris is externally causing issues, wipe the keyboard with a rag and/or carefully remove the debris with compressed air. If the debris is stuck under the key, follow the guide for how to remove the keyboard to access the debris. If you find there is not debris preventing the keyboard from working, there may be a problem with the software on the laptop. Usually performing a factory reset will fix this issue.