Click the first sheet tab you want to group
Hold down Ctrl and click other sheet tabs to group non-adjacent sheets
Hold down Shift and click another sheet tab to group adjacent sheets
Right-click any selected sheet tab and choose Select All Sheets to group every sheet in the workbook
Check the title bar for [Group] to confirm sheets are grouped
Make changes to one sheet to apply them to all grouped sheets
Right-click a grouped sheet tab and choose Ungroup Sheets to stop grouping
Click any ungrouped sheet tab to ungroup all sheets