You should go to Wp-dashboard > Cause > Settings. Here you can configure the Paypal settings and Donate Steps
In case you want to customize the donated amount, you can edit each cause article > and configure the cause options there.
Go to WP-Dashboard > Golden Hearts Options > Settings > Settings > Cause Options
You can see options to choose Cause layout, number of columns, column gap, number of causes per page, number of related causes and others.
You should go to Golden Hearts Options > Header > Header Icon > Enable or disable Donate button
You can edit the Donate button text and choose a featured cause linked to the button.