I'm not a singing-teacher, but quite a good singer.
To use the "chest-voice", you have to kind of relax your throat.
Best way to approach this first is to simply humm. Stand straight an humm tunelessly.
Just "Hhhhmmmmmmmmm.....", be careful not to overdo it, stay relaxed, for if you tighten your
throat you'll notice that your voice becomes higher again. The faster the air streams through your vocal chors, the higher the sound. So don't "compress" the air flow.
You'll notice that your voice get's a bit lower, if you're a "head speaker".
Now add an "aaaahhh" sound to that. Slowly and using a single breath.
Your voice should stay in the same tone as while humming.
If this effect is reached you have found your natural voice tone/level.
Now try and speak from that humming. It doesn't matter what you say, just speak.
Speak slowly and calmly.
If your voice stays the way it sounded while humming you've found your "chest voice".
Practice speaking in this voice. Its just a matter of "adding force" to your voice now.
You'll notice that the "humming" comes from deeper down your chest area than your actual words.
The words are formed by your lips, your tounge and your mouth cavity. So they can be used independetly. Only the sounds basis is produced by the larynx and voice chords.
The three "magic" words are, as always: "Practice, practice, practice!".
If you do this enough, you'll notice that your voice carries better and further.
Have fun training
CU
SaM