On that page there’s a link down the RHS to “Manually building a tile server (18.04 LTS)” that points at https://switch2osm.org/serving-tiles/manually-building-a-tile-server-18-04-lts/.
I guess that the deep link changes when it moved from Wordpress to github?
Since I wrote the reply above https://switch2osm.org/serving-tiles/using-a-docker-container/ has been written which might be easier still.