Steps to Add or Manage ESXi host with Distributed switch in vCenter server 7.0

Login to vCenter server

Select vDS switch -> Right click and select Add and Manage Hosts

Click Add host

Click next

Click new host and select host from the list that you want to add in vDS and manage through Distributed switch

Click next

Select free NIC and assign to uplink 

Check mark on Apply this uplink assignment to the rest of the hosts

Click OK

Now VMNIC1 from all 3 hosts have assigned to uplink 2 

Click next

Click Next and select the correct VMK0 that you want to migrate. In my case I am not going to migrate I shall do it later.

Select the port group name

Select the kernel port and assign to port group, if you want to migrate incase not they click next 

Check mark on Migrate virtual machine networking, if you want to migrate the VM with VM network.

Click next and finish.

Once you will add host it will look like below.