Copper coated steel rod ( electrical wholesalers, ask for earthing rod and clamp) and hammer into ground, water well with water and a little salt ( gets resistance down if the ground is rocky) and leave overnight. Measure AC volts first between the ground rod and line, neutral and the PE connection, using a long length of copper wire to bring the connection from the outside to near to the socket. you should get 220V or so between the live and the rod, around under 10V between the neutral and the rod, and hopefully lower between the earth connection and the rod. If you get that then you can consider measuring earth resistance, but not with a normal multimeter. You need a Ground loop tester, which you can probably hire for the day. Normal multimeters will probably not like the noise present on the wiring.
If this shows there is no earth then call the owner ( if renting) or an electrician to bring the house up to code. Minimum is to bond all sockets to earth, mains earth rod set and compliance certificate. Better to add at same time circuit breakers, and earth leakage on all socket outlets. This will make things safer, and will show up all the degraded insulation by having the earth leakage doing random tripping, so all wiring will have to have in-situ insulation testing done, and all that fails will have to be replaced.