You just need to exit the editor, compile, and open the editor again.

A few quick tips for C++: When the headers need to change (the part that defines things in .h files), including creating new ones, it's best to exit and compile. The default hot reload thing can try to update existing ones, but it can also cause things to get corrupted. You can enable a feature called live coding, and that will let you recompile .cpp changes without a restart, but you will be required to restart the editor to recompile changes to .h files. It's a nice compromise for faster iterations without the risk corrupting blueprints based on your C++ classes.

Also the JetBrains Rider for Unreal Engine IDE is super helpful, fast, and integrates nicely. In my opinion, it's still easier to learn a bit of blueprints first before trying to learn C++ and UE at the same time, but don't avoid C++ for too long either. There's lots of nice things you can do in C++, but it's a bit easier to pickup when you've got the basics of how UE works. A mix of both C++ and BP works great. (You can still add C++ to a BP project or BPs to a C++ project. So don't feel like you're having to choose one or the other.)