Here is the breakdown instruction on how to do it. Hope it will help others in the process... Rather then some ppl just ask to search google.

1. Make sure you computer / laptop are connected to router via cable (Not Wifi, A common misunderstanding mistake for those who use laptop or dongle)
2. Make sure you have Author Cert (With samsung Account) register. Before do anything.
3. Make sure you have Distributor Cert (With Samsung Account) register. This would require your watch to connected with the Gear watch design before you can register them.. P/S: it can be done after step 6
3. Load the the watch face.
4. Press F10 or go to project > Build to build your face watch .GWD to .TPK
5. Press F9 or go to  project > Run on devices
6. Then there is a menu "Connect  to gear" pop up. Click on the plus sign. Key in the IP address you get from your watch. (Setting > Connection > WIFI > WIFI Network > Click on the wifi your on > Scroll down > IP)
7. Make sure you watch is in debugging mode (Settings > Gear info > Scroll down > Debugging mode)
8. You watch will show up on the "Connect to gear" menu. Click on it.

Note 1: If you don't have Distributor Cert registered. The transfer will stop at 61% an error will pop up.
Note 2: Author & Distributor Cert and Registered can be found at Gear Watch design app under Project

Need to click build every single time you want to transfer.