Installation is simple :-
1. Upload all contents of "Upload" folder in MyBB root
2. Go to Admin CP of MyBB and click on Templates and Style Tab
3. Click on "Import a Theme" Tab and import the Peach-theme.xml provided with this package.
4. Click on Import Theme after selecting the xml
5. Select Themes from left tab and from Controls on Right side, Set Peach Theme as Default.