For a basic search you could use the Quick Search.
For a more advanced serach you may use the search function.
In the toolbar click the Search button.
If it is not already selected, select the LDAP Search tab.
In the search dialog type in a search name. Select a connection to search on and the search base DN. Specify a valid LDAP filter and the returning attributes as comma separated list, hit Ctrl-Space to get content assistance. Additionally you may choose scope, limits, alias and referral options.
Press the Search button.
The category Searches in the LDAP Browser shows the searches. You may expand the search to see all search result enties.
When selecting a search the search results and returning attributes will be displayed in the Search Result editor.
When selecting a search result entry its attributes and values will be displayed in the Entry editor.