error during theme upload

Use ftp or the file manager provided by your host to upload the theme you want to the wp-content/themes folder.

another error appeared after uploading the theme, when I installed the required plugins for the theme.

Fatal error: Allowed memory size of 41943040 bytes exhausted (tried to allocate 248 bytes) in /home/yourdiner/public_html/wp-admin/includes/list-table.php on line 129

Please Help Me With This.

If you have access to your PHP.ini file, change the line in PHP.ini
If your line shows 32M try 64M:
memory_limit = 64M ; Maximum amount of memory a script may consume (64MB)

If you don’t have access to PHP.ini try adding this to an .htaccess file:
php_value memory_limit 64M

Or try adding this line to your wp-config.php file:
Increasing memory allocated to PHP
define(‘WP_MEMORY_LIMIT’, ’64M’);

no .htaccess file in the public html folder or wordpress folder

but I added the line to wp-config.php but still doesn’t work.

Is this the site? https://gloriasdiner.com/

https://www.youtube.com/watch?v=ojCnNgvWt9E the error is now fixed

Make note of what you changed as you will have to change it again at every update.