If you have yet to buy your first computer, you will want to have a specific purpose upon finally receiving or buying one. Having a purpose will drive motivation, fun, and gratification while also building other computer skills in the process. A nice choice for a computer newbie would actually be an Apple iPad, which is only $329 and relatively easy to navigate. From there, your understanding can translate to other computer operating systems like macOS or even Windows. Avoid old laptops though, as troubleshooting and sluggishness will frustrate you more than necessary.
Sometimes, your mailbox database does not visually reflect reality. If you have a situation like a deleted message still appearing in your Apple Mail account, you will probably see an error message. A database is a binary blob of information, so it may need to be updated via a rescan from time to time. In the Apple Mail app, select the particular mailbox in the sidebar, then choose "Mailbox" and "Rebuild" afterward. Your mailbox may appear empty until the attachments/messages are all downloaded back to your device.
Peter has stored PDF files on his USB thumb drive and wants to know how to add them to iBooks in his iPad Pro. Leo says that the good news is that the new iPadOS is going to be making this much easier when it comes out in the fall. Then he'll have a files app, which he can connect via a USB-C dongle and copy them directly. Or, he could try putting files into iCloud and then download them to the iPad Pro. Or use iTunes. Lastly, he can email it to himself and open them through the mail app, then save them to iBooks.
Myron has the iPad Pro and he's recently bought a 13" MacBook Pro. But with Apple's new iPadOS coming, does he really need it? Leo says it depends. Leo says that it won't be equivalent to a MacBook Pro, but it will be much improved and will give you a lot more options, including connecting an external hard drive or thumb drive. But if you're just doing everyday things, the iPad is really all you need.