Installing Polygonshotstart.zip, Database unknow?

Hello, im trying to install the Template with the full options contents. After a uploading and unpacked zip file, cannot continuous the install. After included the values for a Database on the joomla installation fields, cannot get the next step. After a clicking the button "weiter" (next) stay the site standby. I checked all the values for a Database, all is correct. What can be the problem?
All its on Joomla 3 Pack running (on Joomla 4 is not a problem its run) Custom like only on joomla 3 works.

Regards, Marco
adress:

Database:

Hello,

1. Try deleting all the files and uploading all the files again. Maybe some files are not uploaded properly.

2. Check with your hosting provider if database parameters are correctly set up with all necessary permissions.

3. Check if the PHP version on this server is PHP 7.4 (it's recommended for Joomla 3).

Regards,
Milos

Yes, is done. Thanks. May be how you say, some file was not correctly uploaded. Some File under Installation folder must be deleted, then is gone.
The next question: Is the Site able to support other languages?? On plan English, German, French
You know some component for 2 or more languages??
Regards,
Marco

Hello,

Our templates come with the English language by default. However, you can install additional languages for every Joomla site. Please read these pages to learn how to install additional languages in Joomla properly and completely:

www.slideshare.net/erictiggeler/creating...-guide-eric-tiggeler

The procedure is similar for Joomla 3 and Joomla 4.

Regards,
Milos

Yes, i know the procedure. Is too long but anyway, is also fun. Sometimes is faster with a Component like Joomfish (not more avalaible)
Regards,
Marco