Install ready-to-paste package (Recommended)
app/code/Mageplaza/Search
folder. In this step, you can copy override Search folder but this may cause of compilation issue. That why you should remove it.php bin/magento setup:upgrade
php bin/magento setup:static-content:deploy
Mageplaza_Core has been already defined
A: Read solution: https://github.com/mageplaza/module-core/issues/3
A: Please follow this guide: https://www.mageplaza.com/blog/magento-site-down.html