How to add some routes into the current proxy? - nginx

Question

I have a problem with adding some new routes to the current proxy which I have on the server .
The current file is located on :
/etc/nginx/sites-enabled/proxy_nginx
with this content :
# proxy cache
proxy_cache_path /tmp/cache keys_zone=cache:10m levels=1:2 inactive=600s max_size=100m;
# redirect all HTTP to HTTPS
server {
listen 80 default_server;
return 301 https://$host$request_uri;
}
server {
return 301 https://$host$request_uri;
server_name www.api.mysite.org; # managed by Certbot
listen 443 ssl; # managed by Certbot
ssl_certificate /etc/letsencrypt/live/api.mysite.org/fullchain.pem; # managed by Certbot
ssl_certificate_key /etc/letsencrypt/live/api.mysite.org/privkey.pem; # managed by Certbot
include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot
}
server {
if ($host = www.api.mysite.org) {
return 301 https://$host$request_uri;
} # managed by Certbot
listen 80 ;
server_name www.api.mysite.org;
return 404; # managed by Certbot
}
Now I need to add these lines into it but I'm confused where to put them :
server {
listen 80 default backlog=16384;
listen [::]:80 default backlog=16384;
location /route1{
proxy_set_header Host decide.externalURL.com;
proxy_set_header X-Real-IP $http_x_forwarded_for;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Host $server_name;
proxy_pass https://z.externalURL.com/route1;
}
location /route2 {
proxy_set_header Host api.externalURL.com;
proxy_set_header X-Real-IP $http_x_forwarded_for;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Host $server_name;
proxy_pass https://api.externalURL.com/route2;
}
I know that I shouldn't have a duplicate default-server because I wasn't able to add the above lines into my default nginx.conf file.
So the question is how to mix these lines into the /etc/nginx/sites-enabled/proxy_nginx file.