Say "Yoo hoo!" as if calling across a playground, and then do a pirate "Yo ho ho," and you will get your own chest voice and head voice right away. Feel the resonance. My old voice teacher (long ago and far away) had me work a lot on physical placement of the voice in the throat; humming with mouth open, to literally get behind my voice break. Blending them involves having some head resonance when you sing chest, and some chest resonance when you sing head. Developing your voice is work; rewarding, good work.