You also need to understand how you currently track orders. If you have a real store without online sales, you need to come to you, it will be very difficult to evaluate the effectiveness, in this case you can only focus on questions in the group about availability, price, etc. That is, the goal of "increasing sales" is useless.
Increasing brand awareness by increasing latest phone number database engagement. This is painstaking ongoing work for those areas of activity where it is not possible to track the exact number of attracted clients. In this case, a group in social networks is a point of contact, a platform for notifying about the life of the company. The result of these actions can be assessed using the following indicators: increasing/maintaining audience reach, subscriptions to notifications about group updates, engagement in discussions/surveys, feedback from clients - reviews.
Increased traffic from social networks to the site. If all the main activity occurs on the site, it makes sense to send all network users there, and then evaluate the result based on metric data.
Getting leads from a group. I think everything is clear here. We count all requests in messages to the community, on the wall, to photos, etc. But do not forget that leads can become a sale only if the manager/seller works well.
Other local goals. Here everything depends on the circumstances: it could be informing about a certain product, attracting an audience to an event, conducting a survey, etc.
Sales through a group. Yes, for some areas such a goal is possible, I will dwell on this in more detail in one of my next articles.
If you set an adequate goal for yourself and understand that social networks do not work for sales in all cases, it will be easier for both you and the performer to work.
Look at things realistically, social networks have huge potential, because almost any target audience can be found there, but in order for them to buy from you, you will have to put in a lot of effort.