You may only appeal a permanent ban or a block that is a year or longer. Temporary blocks will not be granted appeals.
Submitting an appeal does not guarantee an unban, but it is a possibility. If your appeal is successful and you are unbanned, but you go on to get permanently banned a second time, then you will not have a second unban.
In order to have your appeal processed, please fill out this form: https://forms.gle/TQPAPo9ANgarus5F8