Hello,
to control what clients store and send to the SEPM:
Clients panel > select a group > Policies tab > Client Logs Settings (all is enabled by default)
To control how long the SEPM stores the client logs in the DB:
Admin Panel > Servers > right-click on the DB and select Edit DB Properties > Log Settings
For any further detail, click the button "Help" on the bottom of almost any window of SEPM.