@debecha No you need to connect Ethernet Cable from Archer C6 to Deco M4 to give internet connection and then you can connect the other Deco M4 unit over Wi-Fi.

  @debecha Yeah im also using Deco M4.

  @debecha 

The Archer C6 router has a Wi-Fi range of approximately 1,500 to 2,000 square feet. The range of one Deco M4 unit is approx. 1,900 sq ft. So you could get rid of the Archer C6 and use your two Deco M4 Units as long as you don't need to go beyond 3800 square feet. This would also allow you to use the seamless roaming feature of your M4 Deco's 

  @debecha Yeah go for Deco M4 only or if u want to use Archer C6 so you can also add one more Archer router to extend the range and seamless roaming by using Easymesh or Onemesh but you can't use Easymesh or Onemesh technology with Deco Mesh Technology because all the (3) different Technologies.