Any websites can help to prepare interviews?

So, I have this free 90 day trial code for intelliJ IDEA Ultimate I got for enrolling in this udemy course. And, I don't need it anymore because I can use my student email to get access to jetbrains software, ie intelliJ ultimate. So, if you want to try out inteliJ ultimate for 3 months, let me know and I can give you the code... somehow. I'm not sure yet. Maybe Google Hangouts?

So my CEO wants me to move to architecting systems!!!!!!!! My dream since a kid !!!

It seems like a mad job where you're a crazy scientist 😂
What should I read or do to be better ?

Confession:
I've been working as C# programmer for an entire year, and I wrote desktop app as well as win services, but when it comes to practice (cause I moved to PHP about 7 months ago) on Codewars I go completely wrong, and it's even worst on Hackerrank.
Have to admit, feel so dumb and lost