how can i build a pc like this

Solution
The picture you shown was not just a simple water cooled CPU rig.

It has a CPU and GPU liquid cooled (and not with water) with dual radiators, and custom made piping.
The cooling block for the GPU looks to be completely custom, which is expensive as is.
Those pipes are not just rubber pipes bought off ebay or unknown third party amazon vendor, those are custom made metal pipes with exact bends with the ends flared for the pipe fittings. This is a professionally built rig, likely done in a full fledged fabrication shop.

As another user stated, they could have easily paid 1500 for the fabrication and powder-coating of the cooling system alone, let alone the cost of the actual PC parts.

To put it into perspective, the linked PC is not...
The picture you shown was not just a simple water cooled CPU rig.

It has a CPU and GPU liquid cooled (and not with water) with dual radiators, and custom made piping.
The cooling block for the GPU looks to be completely custom, which is expensive as is.
Those pipes are not just rubber pipes bought off ebay or unknown third party amazon vendor, those are custom made metal pipes with exact bends with the ends flared for the pipe fittings. This is a professionally built rig, likely done in a full fledged fabrication shop.

As another user stated, they could have easily paid 1500 for the fabrication and powder-coating of the cooling system alone, let alone the cost of the actual PC parts.

To put it into perspective, the linked PC is not the equivalent of a homemade hot-rod at the race track,but a million dollar professional outfit that has the resources to use advanced software to figure out what angle to adjust the front bumper diffuser for the current track.

This is the kind of PC that a major vendor like ASUS or Gigabyte or Corsair built as a demonstration, not as a practical PC
 
Solution