Sales Managers are front line managers of a sales team. Typically, sales managers are not responsible for selling but have a team quota goal they are responsible for achieving.
Sales managers spend most of their time helping their direct reports exceed their individual revenue goals. The two main levers for managers are increasing motivation of each individual on their team (inspire them to work harder through setting goals and creating incentives) and increase the efficacy of their efforts (through training, skill development and process improvements). Generally speaking, Sales Managers will manage direct reports and will not manage other managers (that's typically the role of a Director level or higher executive).
Sales managers may also be responsible for strategic projects or one-off initiatives that have been delegated from the executive team that aligns with their span of control and expertise. For example, an SDR Manager may be responsible for choosing the right third party software tool to be used in prospecting while an AE Manager could be responsible for building unified sales scripts and collateral in the course of selling.
Another typical responsibility that most Sales Managers carry is hiring and firing. Typically, Sales Managers spend a good portion of time growing their own team through recruiting, interviewing, and then onboarding/training new hires. Once a new hire is fully ramped, Sales Managers tend to shift their focus more onto performance management and ensuring their reps are hitting goals or insuring performance improvement plans (PIPs) to manage them out of the organization.
Typically, sales managers are promoted from within or hired into a role in which they have previous management experience in a similar type of sales process and methodology. Since most of their impact is seen over a longer time horizon and they are not responsible for direct sales, most Sales Managers derive a higher proportion of their total earnings through their base salary and have less volatility in earnings versus an individual contributor. As such, a Sales Manager can often earn less than the top performer on their team.