Before running the uwsgi ini file you will need to add a line to it to create logs.

Something like:

#location of log files
logto = /var/log/uwsgi/%n.log

uwsgi docs

Then you will have to create the directory in your VPS (not that you can create the directory in whatever path you want, as long as it's the path that you have in the ini file):

sudo mkdir -p /var/log/uwsgi
sudo chown -R user:user /var/log/uwsgi

If you want to see the logs you can cat command them in the terminal.

Nginx error logs default location is:

/var/log/nginx/error.log

As for debugging (correctly) that is a skill beyond my current abilities!