1.7kg Coopers Mexican Cerveza extract can (or Muntons Mexican Cerveza etc)
1kg Coopers Brew Enhancer 2 (see here for BE2 ingredients)
Add 2 litres (2 quarts) of hot (recently boiled) water to your fermenter.
Pour in and dissolve the can of extract and BE2.
Top up the fermenter with cold water to 21 litres (5.5 gallons).
Check temperature of wort and adjust with hot or cold water to get close to 20c/68F at 23 litres (6 gallons).
Mix in yeast when wort is 20c/68F.
Try and let the wort cool down over the next couple of days to as low as 13c/55.5F.
Ferment at 13c-20c (55.5F-68F) for 10 to 14 days.
Bottle or keg as usual.