Using a different startercharacter than what's inside of starterplayer

Not sure where to ask this question but is it possible to play as a different character other than the one you have inside of starterplayer?

Just rename that character to StarterCharacter and put it inside of startplayer…?

You can use Player:LoadCharacterWithHumanoidDescription, you made need to create HumanoidDescription for different character for this to work.