NextCloud installation Ubuntu 20.04

i am trying to install the nexctcloud through ubuntu terminal. I have done all the installation. I could not open the webpage of Nextcloud. How can i troubleshoot this?

Thank you

Please post details. Which installation guide do you use?

Here my favorite installation guides.

Ubuntu 20.04 with nginx

Debian 10 with apache2

You can combine both e.g. Ubuntu with apache2.

Ubuntu 20.04 with apache2 i already installed mariadb also. still webpage not working

Do you have some errors and logs? Are all services active and listen on the tcp ports?

I didnt get any errors during the installation. I checked Apache2 and Mariadb status. It is active and running. do i need to install also nginx?

No. In normal installations you only need apache2 or nginx.
Does the webserver works? Look in the apache2 logs /var/log/apache2 …

which command i need to exactly write to view logs?

tail -f /path/to/logfile
sudo tail -f /path/to/logfile

Then you see in realtime new entrys while accessing the service.

man tail
tail --help

Please increase your linux and gnu knowledge.
On server failure you will need it.

i have this error ‘cannot open. No such file or directory’

Sorry. I do not know the location. Search.

sudo find /var -name "access.log"
sudo find /var -name "error.log"

man find
find --help

Looks like there is more missing.

If Apache is installed without changing the configuration you will have access to it using the IP of that device.
Is it in your local network or on a remote server?

I assume by ‘installation’ you mean installation in Ubuntu? How did you install Nextcloud?
Did you create a database? Do you already ‘see’ nextcloud when you go to the ip address?

Make sure you have the right ip address. Go to your router and look for the list of attached equipment there you find the right ip-address for sure. if you are at the right address something is going to be seen. Make a snapshot with Windows and post the photo. Then we can make the next step.

Look at Howto Install NextCloud 20 on Ubuntu 20.04.1 The classic way [Wiki] and compare what you have done during install.