How do I wire my dimmer switch,Iconected to an existing wire and am connecting the dimmer to a wall I made?

Question:I am building a shower next door,I built a wall and want to put my dimmer switch on the new wall,to control the lites i am installing.
Do I connect all the white wires together on the light itself.At each light or white to white,blake to black ,ground to ground ect.?

Answers:
Your question isn't very clear, but I assume your bathroom/shower light fixture has multiple bulbs, each with its own white, black and ground. Your supply line which runs from the fixture(s), to the dimmer switch and ultimatey to your breaker will also have white, black and ground.

It sounds like you built a new wall, so you will need a line coming into the switch box that has ultimately connects to the breaker box. That will bring power in, then you need to run wire to the fixtures - bringing the power over.

Take all your fixture wires and connect them to the corresponding supply line. whites on white, black on black. Secure the connection with a wire nut.

Wire the switch per the instructions. Be careful, turn off power at the breaker before starting. Go to Homedepot or Amazon and buy a book on basic wiring. You'll be a lot more knowledgable and certainly safer. If you get in over your head, call an electrician.