I see Forwarded inputs type File & Directories is monitor only not collect log to Splunk Enterprise.
How to store log with Forwarded inputs type File & Directories.
You are asking basic questions, you should start with splunk education this will give you an overview
please have a look at following links
Free Splunk Fundamentals 1 https://www.splunk.com/en_us/training/free-courses/splunk-fundamentals-1.html
Free Splnk Educational videos https://www.splunk.com/en_us/training/videos/all-videos.html
Learn how to use Splunk https://www.splunk.com/en_us/view/SP-CAAAG2R
Splunk Architecture Overview (e-learning) https://www.splunk.com/view/SP-CAAAHSJ
Download Splunk Enterprise for free and start exploring it https://www.splunk.com/en_us/download.html
Free trials and download https://www.splunk.com/en_us/download.html