The spider add-on runs in the background and collects information about your site to use in the text search and for diagnostics.
The spider is installed automatically when you add any add-on that uses it. To install it by itself, from ADMIN HOME, click on MANAGE ADD-ONS and then ADD-ON MANAGER. Scroll down to SPIDER on the right side of your screen, check the INSTALL box and click OK to install the Spider.
The only setting necessary to make the spider run is to enable it. To do this, login as an administrator, click the ADMIN HOME, then MANAGE ADD-ONS, SPIDER and finally SPIDER SETTINGS. When the record opens, click ENABLED. Click OK to save the settings change.
There are several other options to control the spider process available in the options tab of the Spider Settings page, each is documented on the settings page.
To search PDFs you must install Acrobat Pro on the webserver. When installed, open dcomcnfg and make sure your process can launch the AcroExch.PDBookmark DCOM.