I’m starting the testing phase for my web application and i’m confused where to start or what method is the best.

I fineshed develpoing a web application using asp.net core mvc which contains multiple of controllers, models, view models etc. and has functionalies such as, personal accounts, roles and prevlages, create, remove, lock accoonts crud functions on multiple objects.

i’ve read about unit tests but couldn’t fully understand how it works on my project which is not a calculater or wheather degree converter :)

i would like to know how test if all functionalities is working as expected

any given opinions or articles with examples/demo is highly appreciated