So far we’ve used a water system analogy to explain voltage and current. Remembering that analogy we said voltage was like a water pump that can provide pressure to the system and current is how fast the water is actually moving through our pipes (wire). Resistance would be anything introduced in our system to slow the flow of current. Think of pinching one of our pipes or inserting a flow regulator. Those things resist the flow of water. Similarly, resistors resist the flow of current.
The continuity tester is probably my favorite feature on the multimeter. Once you start building more complex circuits and specifically if you make some homemade printed circuit boards you will want to know if parts of your circuit that should be connected together are actually connected together. The continuity tester will be your best friend on those situations.