Do a search on youtube for something like 'how to use a multimeter' or 'using a multimeter'. They are also sometimes called DM, DMM, volt meter, current meter, etc. There are probably several out there that will not only explain but illustrate their uses. The video instruction is probably better than trying to explain in written text anyway.
Most multimeters purchased new should come this instructions. I have one more expensive meter that has instructions that I still refer to occasionally.
