best way to do this is having access to a lab with some actual devices (L3 switches and routers), and preferably an Ethernet tester. baka me access ka sa ganito at work? madali maintindihan (at tandaan!) if you can observe the behaviour after making config changes.
actually, kung meron kang specific questions (which specific protocol, or anything)... ask and i may be able to point you to some material that can help, or explain it myself. i work for a company that makes routers and radio links. we sell our gear to (among others) telcos deploying 4G/5G networks all over the world, including the Philippines. it was my job to test that the features/functionalities work. customer issues, e.g. interoperability with Cisco, Juniper, Nokia, Huawei, etc., na hindi na-solve ng tech support get back to engineering - which usually started with me.
note, i'm not CCNA - did the bootcamp, pero di na nakapag-exam. i got pulled up at work, different responsibilities, although still called upon for help.
don't misinterpret this as being negative, but you won't learn about all these things (networking) by siimply preparing for, and passing the CCNA exam. however, it's a very good starting point. kung gusto mo talagang matutunan, it's very nice and very useful to have this knowledge. also, 3 years lang validity ng certification, but if you want this on your cap sa pag-apply ng work do it.
good luck!