Pretty much. With Kirby, against most characters, you generally to use tilts or grabs to force your opponent in the air, and then attack them there, because Kirby's aerial game is good. You also want to get your opponent offstage, and attempt to gimp them with Dair or Bair, or maybe a Stone if you've gotten good enough to be used to the timing. Stone generally doesn't KO them unless you get lucky and stagespike them, or if their damage is really high.
A few basic "strings" of moves you should know if you're new, that generally work pretty well: uptilt can lead into more uptilts against heavier characters, dthrow can lead into uptilt or chase->regrab, Fthrow->uair works against most characters at 0%, fthrow->jump->Fair works against floatier characters, or at around 15%, Dtilt->Fsmash can KO if the dtilt trips them, Dair->Fsmash can KO too sometimes. Uair->bair or Bair->bair works well. Sometimes Fair->fair too.
Your best KO move is of course Fsmash, but don't be too predictable with it because it's easily punished if they shield it. Aerial hammers are good too if you're careful with them, and Bair is a good KO move if it's fresh and their damage is pretty high. If you're really hurting for a KO, grab them and Upthrow at high percents, it can KO, depending on how heavy they are, and what the stage is. Like, You can Upthrow Game and Watch on the top platform of Battlefield and probably get a kill at less than 110%.