Looking to create a dashboard to allow users to lookup usernames, information, and groups within the Active Directory data. How do I create a search for this?
You could start by integrating your Splunk with LDAP so that your dashboard searches the AD data using LDAP queries. This app should help: SA-ldapsearch - https://splunkbase.splunk.com/app/1151
First you have to think what exactly components in your dashboard would search for.
Then you have to check if you have data to search from.
After that comes time to write searches which do search for those things.
Last step is making the results from those searches into some visualizations or make them dynamic based on dashboard inputs contents.
So where are you in this process?
It looks like, you have the data, why not go through some training on creating some generic stuff, this is free online guide, good starting point, you learn some basics concepts, you can apply the principles to the AD data, and then further develop your skills by looking formal training ones.
https://docs.splunk.com/Documentation/SplunkCloud/9.1.2312/SearchTutorial/WelcometotheSearchTutorial