The formal-form ("desu"-table) using if you e.g. with teacher or with another higher person speaking...
And the daily-form ( "da"-table) using if you with your family or with friends (how I)...etc. speaking...
E.g.: I'm would your teacher be, then would you to me say: "O-hayou degozaimasu x-sensei! (Good morning x-teacher!) Kyou wa ii tenki desu ne~ (Today is a nice weather~)". And I if your firend would (but we are), Then so: "Kimi ga ii da (You're nice...)...etc."
I find that the best way to learn kanji is to get some Japanese reading material and have a dictionary beside you as you go. It's painfully slow but it gets absorbed.
Sorry if interrupt, but do you upload comics? If yes, can you please upload this comic, author uploaded it on fanbox, but fanbox delete almost all posts, and kemono stop working in the same time, and almost 2 years i try to find it somewhere else, but useless, Thanks in advance, and sorry for bad english.