Whatever Yamaha powered mixer you choose, connections are fairly simple. Plug in the main vocal microphone XLR to input 1; use additional channels (2-4) for backup vocals, if any. If there are no backing vocals, use these, plus additional channels, to plug in microphones placed at the guitar and bass amps. If you have enough inputs, miking the kick drum and overheads on the drum set can also be done. Next, connect the PA speakers to the main outputs, and, if you have them, stage monitors to the sub outs on the side of the mixer.
If you don't have a mixing engineer for your band and plan to do it yourself, sound check is critical to getting the sound right. Turn on the phantom power button to send power to the mics, then start with the kick drum and bring the levels up in the mix. Next, get the lead vocals set, then proceed with the bass, the guitar and other instruments. Check your monitor mixes next so that each person with a monitor has a mix of instruments they want at a sufficient level. If any of the musicians are playing with direct in boxes instead of amps, it is important they check their monitor level with the full band doing a song to make sure it is loud enough. After setting all the levels, run through a couple of songs and check that it is okay.
Yamaha powered mixers have EQ functions that will let you tailor the frequency response of the main mix in the room your are playing. Basic mixers have high, mid- and low EQ for each channel, while more advanced mixers give you more frequency control in the EQ on each channel. The mixers also have effects that can be applied to individual instruments, including reverb, echo, chorus, flanger, phaser and distortion; adding reverb on any DI'd instruments can help warm up their sound. The effect level can be controlled from a knob on each channel. The mixers also have an RCA stereo output channel so you can connect an external recorder such as a DAT, a CD burner or a flash recorder to record the performance.