Welcome!

1 - Take or Download zip file which contains the given files
.crt, bundle and .key file

2 - If file doesn't conains the key file and key into txt file then perfom given command
openssl rsa -in generated-private-key.txt -outform pem -out generated-private-key-new.key

3 - merge .crt and bunndle file into single file as chainfile.crt

4 - Execute given command to check key with bunndle
openssl x509 -in bundle.crt -noout -modulus | openssl sha1
openssl rsa -in new_key.key -noout -modulus | openssl sha1

5 - Move this files into /usr/share/ssl/certs/test.test.com(directory with domain name)/

6 - Open .conf file from /etc/nginx/sites-enabled/ and user given command at last
ssl_certificate "path of bundle file";
ssl_certificate_key "path of key file";