C wire confusion

Trying to install thermostat. No c-wire to thermostat but c-wire and one other connected at control panel in furnace from a different wire harness.
Do I:

  1. Just install c-wire adapter and leave all other connections intact?

  2. Can I use another wire in the existing wire bundle to thermostat and connect one to c terminal in furnace (leaving all other connections) then to wyze thermostat as c?
    Thanks in advance for your help!

I do not know how to post images from my phone into forum.

Not much of an HVAC person, sorry I cannot provide much help with your wiring issue. But I can assist with the posting of the pic

When you are creating or editing a message click on the upload button on the bottom right

Follow what @R.Good provided for posting the Pic. Would be great to see a picture of your existing T-Stat Wire and connection points as well as your HVAC setup where the wires connect to your control board.

Added a couple photos, first of board in furnace, second just of additional thermostat wire that connects to c at furnace board, third of thermostat


Connect your C adapter as follows:


Finally got a chance to try this today.
Works perfectly.
Thanks to all who spend their time helping.
It is really appreciated!