Labs and commands

I have just started my devops journey and doing the course of Devops pre requisites. I am following the videos in a sequence but when I start doing labs sometimes I found totally different tasks or commands which are not covered in the videos and for these I have to look up on the hints or solutions. For example To change the port in python app.
sudo sed -i ‘s/8080/5000/g’ app.py; python app.py
This is the totally different command for me which I just ran but didnt understand completely. Am i doing the right thing by just following the hints on the labs?

You won’t find every single command and all its options and how it can be used in a course. You will have to do some research in harmony with your learning. Most Linux commands have built in help, there are also the man and info pages and then there is the wider internet which can be searched with your favourite search engine.

At the start it can be very overwhelming but as you progress you will begin to understand much more and the learning experience will become more pleasant.

Also you can ask all the questions you like here.