To make egg tempera you need one egg, put the egg white off, and then take the same amount from line seed (or line seed varnish) as you have egg yolk in the glass. Shake. The third step is to put 1 part up to 3 parts of water in the glass (measured on the egg yolk). Shake well. Most important: before putting the water into it, get the line oil seed (-varnish) in it. First line oil, shake it, then the water.
To make tempera out of more than only one egg, i would take a second glass, mix always one portion there, and then pour this into the first glass.