Now you can build Scouts (since they`re not aggressive ships, they won`t bring you of you DP, if you build attacking ships like T.ryu jin you will get out of DP) and explore planets without fear. After you explore 5 planets, go to the "Projects" page, then "Colony upgrade", then "Colony Cluster level 1". Then it will show your normal planets ID`s that are nearer to your homeword, select one preferrably with Terran Metal and click "Confirm". Now those 5 planets are only into one colony!
Go to Manage Colonies, choose your brand new Cluster level 1 (C1), build the max ammount of Mining on your planet you can, now you will start getting ore from that planet with every turn you use (note that it stops after the ore on that planet ends, to see how much ore it got open your`s planet page and check the "Available ore" line on the first column). Now you can disband your Viators so you won`t lose money from their upkeep, and go to the Research page and start researching the Technology tree (this enables you to build new and better ships later). After the ore on your C1 ends, if you have more than 2000 ore you can go to the market and sell your ore for 10000 a piece!
Now you can plunder your C1 and repeat the process, that is called "strip mining". After you get like 500 millions money doing that, you can start exploring for good planets with high land, cluster them and build agriculture. Also research agriculture infra.
Have fun