If you purchased the Advanced Feature Set for PocketBible for Windows Store on our website, simply open PocketBible and the Advanced Features Set will be automatically applied. You should see a message telling you that it is enabled.
If you purchase the Advanced Feature set inside the PocketBible app, the Advanced Features Set will be automatically applied immediately after the purchase is complete. You should see a message in that case as well.
To verify that the Advanced Feature Set is installed, bring up the Settings pane in PocketBible and choose About. At the top of the pane you should see "PocketBible for Windows Store with Advanced Features" if the AFS is enabled.