To enable the CIS feature navigate to Settings > Configure system > Toggle features.
Click on the Accounting tab in the column on the left.
Tick the check box beside the Construction industry scheme box.
Once enabled the system will display three new revenue codes, and three new cost of sales codes specifically for CIS on the Settings > Accounting > Account codes menu.
Use the appropriate CIS account code when creating new invoices and bills. A CIS return can be created on the Reports > CIS menu on the Monthly returns tab, this can be submitted via Clear Books directly to HMRC. A CIS suffered report can also be created showing CIS deductions on your sales invoices.