I need a way to make my voice louder for a costume. Can somebody give me suggestions on how to do it?

Hey guys, so I want to build a big costume, and the only problem so far is that nobody would be able to hear my voice underneath a mask. Anyways, I have a soldering gun and some electronic components. I would just use a voice changer except that it is hard to understand. So I was thinking I would like to put a microphone in the helmet, the only problem is I do not know what to do after that. I want to connect the microphone to a speaker or a mini amplifier, but I don't know how to do that. I essentially just want to speak into the microphone and have it connected to an output such as a speaker or an amp and have my voice very loud so that people can hear me. Please forgive my lack of knowledge on the matter. If you could provide me with a youtube video, that would be the best help. Thanks.