Great to hear!
I’d recommend Visual Studio Code with the Motoko extension, see “Install the language editor plug-in” here: https://sdk.dfinity.org/docs/quickstart/quickstart.html
The Motoko base library is installed with the sdk, importing is easy: Importing base library functions :: Internet Computer
And the repo is here for reference: https://github.com/dfinity/motoko-base/tree/master/src
There are some great example projects on github worth exploring, a few to get started are listed in this thread: How to learn Motoko with no experience? - #5 by Ori and you can find some more on the Awesome DFINITY repo too: https://github.com/dfinity/awesome-dfinity