You can install free version of “WP Smart CRM & Invoices” from side menu ->plugins->add ->search “smart crm”->Install now or download it from WP repository: https://wordpress.org/plugins/wp-smart-crm-invoices-free/
In order to install PRO version you should have purchased it on https://softrade.it/servizi/wp-smart-crm-pro-plugin/. You will find the plugin in your account from download area. In order to installa new updates, you should deactivate and delete the plugin and upload the new file..
IMPORTANT: before activating PRO version, make sure you deactivated FREE version, or an error will occur and you won’t be able to activate the plugin.