But if someone asked me about lightning network, how to open a channel or somewhat script/code, I have no idea about it.
You can read this about lightning network:
A Beginner's guideline to Bitcoin Lightning NetworkThe Lightning Network FAQElectrum Lightning Network walkthroughLightning Network ObserverAll Lightning Network Threads In One PlaceFor ease, you can recommend wallets like Bluewallet if you are introducing someone to how to use lightning network if wallet like Electrum is not easy to understand. But for Electrum, I included a guide in the link above that will be very helpful for you.
This reminds me when I started on this forum, I go online for what I do not know, some experienced members always correcting me, I accept corrections but this does not stop me from reading online contents to gain more understanding. I seek for the books some experienced members on this forum are reading that helped them, some recommended me some books and the correction later reduced. Do not be affraid to post your opinion, if you are corrected especially by experienced members, accept it and you are already learning in the process. Read quality posts more than what you are posting.
But never post what you do not know about, you can ask question(s) on a newly created thread. Research more, request for articles you can read for a particular topic. Post your opinion, you will be corrected or not and you will learn more. It all means you are getting better than before.
Does we need to practice and learn anything about Bitcoin to understand it all? e.g. setting up Bitcoin core, try to open new channel, try to mining yourself etc. I think that's costly enough, Bitcoin core need insane memory and to mine Bitcoin I need to buy mining rigs and many more... that's why I'm looking for the alternative (using electrum and not mine Bitcoin, but buy to hold). It's possible if I can understand those thing without practice and only read from other people experiences?
If you are pratical about something, you will have more knowledge, if you are running a full node on a full client like Bitcoin Core, you will be able to answer question related to Bitcoin Core. I like to be practical, if you use Electrum which is the most reputed light client wallet on this forum, you will be able to answer questions partaining to it. If you read what experienced members are posting, you will also be able to answer some questions asked later.
If you need more information, you can ask.