There are a lot of ways you can customize your OPAC in Koha.
Decide how you want your OPAC to look & what content you want on the main page
Create a library branded stylesheet using CSS
Do not edit the default CSS files, instead create a new one, that way the system can always fall back on the original CSS.
Create a custom XSLT stylesheet to change the way search results and bib records appear in the OPAC
OPAC System preferences
OPACBaseURL : Enter your library's url
opacuserlogin : Decide if you want to allow patrons to login to the OPAC to access customized functionality (searching will be allowed without logging in)
RequestOnOpac : Decide if patrons can place holds via the OPAC
OpacPasswordChange : Decide if patrons can change their password (don't allow this if you're using LDAP)
OpacRenewalAllowed : Decide if patrons can renew their checked out items via the OPAC
opacreadinghistory : Decide if patrons can view their reading/checkout history via the OPAC
reviewson : Decide if you want to allow patrons to comment on bib records via the OPAC
OpacStarRatings : Decide if patrons can leave star ratings
virtualshelves : Decide if you want patrons to be able to create Lists
OpacAllowPublicListCreation : If patrons can create lists then decide if they are allowed to create public lists
suggestion : Decide if you want patrons to be able to submit purchase suggestions
OPACViewOthersSuggestions : Decide if you want patrons to be able to see purchase suggestions made by other patrons
opacbookbag : Decide if patrons can save items into their cart
AnonSuggestions : Decide if you want non logged in users to be able to make purchase suggestions
LibraryName : Enter your library name for display in the <title> tag and on the top of the OPAC
opaccredits : Enter HTML to appear at the bottom of every page in the OPAC
OpacMainUserBlock : Enter HTML that will appear in the center of the main OPAC page
OpacNav : Enter HTML that will appear to the left on the main OPAC page
OpacNavBottom : Enter HTML that will appear below OpacNav
OpacNavRight : Enter HTML that will appear below the login box on the right
opacheader : Enter the HTML that will appear above the search box on the OPAC
OPACNoResultsFound : Enter the HTML that will appear when no results are found
OPACResultsSidebar : Enter the HTML that will appear below the facets on your search results
OPACMySummaryHTML : Enter the HTML that will appear in the far right of the circulation summary in the OPAC
Customize your stylesheets:
OPACUserCSS : Enter any additional fields you want to define styles for
opaclayoutstylesheet : Point to a CSS file on your Koha server
OpacHighlightedWords : Decide if you want search terms to be highlighted on the search results
hidelostitems : Decide if you want to show patrons items you have marked as lost
BiblioDefaultView : Decide what view is the default for bib records on the OPAC
OPACShelfBrowser : Decide if you want to enable the shelf browse functionality
OPACURLOpenInNewWindow : Decide if URLs clicked in the OPAC are opened in a new window
SearchMyLibraryFirst : If you have a multi-branch system decide if you want patrons to search their library first
OpacAuthorities : Decide if you want patrons to be able to search your authority file
OpacBrowser : Decide if you want patrons to browse your authority file (French libraries only)
OPACSearchForTitleIn : Choose which libraries you want patrons to be able to re-run their search in
OpacAddMastheadLibraryPulldown : If you're a multi-branch system you can add a pull down to the search bar for patrons to search which library to search
EnableOpacSearchHistory : Decide if you want the system to keep a search history
Set up your cron jobs
If you have the OpacBrowser preference set decide when you want the contents to rebuild (French libraries only)
If you have custom RSS feeds, decide when you want the feed to be populated
Using the OPAC system preferences you can customize various regions, the following graphic will define what preferences update each of the regions in the Bootstrap theme.