Installing the element web-client on a server is actually incredibly easy. It's entirely client side, so you just need a webserver that can server static files.

Download and unzip a release tarball: https://github.com/element-hq/element-web/releases

Place the folder somewhere, maybe /var/www/html/element. Inside that folder, copy config.sample.json to config.json. This config file allows you to change some theme settings or configure a different default homeserver which is probably what you want to do.

Updates just involve downloading a new tarball and extracting it into your webserver directory.

My caddy config looks like this:

element.nilsu.org {
  root * /var/www/html/element
  encode zstd gzip
  log {
    output file /var/log/caddy/element.nilsu.org
  }
  file_server
}