Hello, congrats on the offer!
It´s great you want to spend some time on this, and even better now half of the world is locked down...
My recommendation would be:
- Excel & financial modeling > Training The Street (e.g., Financial Modeling, Valuation, pivot tables, statistics tools, etc.) Sucess here would be to forget your mouse and do everything with your keyboard.
- Power Point (This is also sooooooooo important) > Read "Say it with charts" and "Pyramid Principle" and try to replicate later good presentations in PPTX (e.g., you can take any of the ones published in McKinsey Global Institute that are also a fanctastic read!)
Hope it helps!