further to Jeff and Grant's posts, some additional reading on backups (including the importance and meaning of RTO and RPO), can be found in the following link. If you are in the position of being asked to look after your companies servers without the benefit of much SQL Server DBA experience and training, the link is a collection of articles with training, reading and advice for what is known in the SQL Server world as Accidental DBA's - people who have suddenly found themselves, possibly unexpectedly, looking after a SQL Server Estate.

The articles are from a company called SQL Skills, they're held in *very* high regard. Even by the likes of Grant and Jeff, who also have something of a reputation in the SQL Server world.

https://www.sqlskills.com/help/accidental-dba/

Hope you find it useful