Hi, Robert. This is real easy and the new fixtures that I have purchased recently come with directions, some of which are sort of in English. Have someone watch the light while you remove fuses or turn off circuit breakers to cut the electric power to this sircuit. Leave the room light switch on. Remove the old fixture. When you can get to the wires, remove the wire nuts but don't let the wires touch or don't touch the bare wire until you have check to assure that the poser really is off using a circuit tester. Connect the bare ground wire to a screw on the box in the ceiling or to the bare wire end that you find in the box. Undo the black house wire from the black wire that is on the old fixture. Connect the black house wire to the black wire from the new fixture using a wire nut of the correct size. These are sometimes supplied with new fixtures or you can purchace a few where you bought the new fixture. Sometimes the outside of the new fixture package will say if you need wire nuts or not. Now go through the same process with the white wire that you did with the black wire. You may have to move the screws that held the old fixture in place to mount the new fixture or install the screws that come with the new fixture in the ceiling box. The instructions should give you some clue about what you will have to do. Now put the new fixture in place folding the wires into the ceiling box and tighten the the screws that hold the fixture. Put bulbs in the fixture. Now screw the fuse back in or turn the circuit breaker on. The light bulbs should illuminate.
Since there are so many different kinds and styles of fixtures, it is impossible to cover every contingency on these but you should be able to figure out what is required from the instructions or pictures. If you have any doubts about the process at all, have a professional do it or ask the old man in the electrical department of your closest home center. Your home center should also have books with photos of this and other electrical problems.