Installation
I. For simple general way to install
Go to Plugins → Add New →Upload
Browse and Upload the downloaded zip file
Activate the plugin.
II. For familiar FTP users
Extract the plugin zip
Upload plugin zip to /wp-content/plugins/
Go to Plugins → Installed Plugins → Active
Configuration
1) Installation of PDTFK
I. General Installation of PDFTK Follow the link
https://www.pdflabs.com/tools/pdftk-server/
II. For ubuntu System
sudo apt-get update
sudo apt-get install pdftk
III. For Centos or Redhat linux
https://www.pdflabs.com/docs/install-pdftk-on-redhat-or-centos/
Once installed the PDFTK
2) Go To Plugin Settings Page wp-admin > Gravity Merge > Settings to put the PDFTK path
– Normally the PDFTK path will be like “/usr/local/bin/pdftk” or “/usr/local/pdftk”
3) You can also check “Use Our PDFtk Library” check box. In this case you wont need local installation of PDFTK or PDFTK path.
Once Configured you are ready to use the PDFTK library and the Gravity Merge Plugin