First navigate to StarAtlas official website:
https://play.staratlas.com/ 

Press the “Play now” button, and connect your Phantom wallet. Choose Approve from the Phantom wallet Menu that appears. All transactions cost a small amount of Solana so always be sure to have enough Sol to cover the fees. 

Pick which faction you wish to join. Each faction has its strengths and weaknesses so its recommended you do some research before picking your faction. You wont be able to switch later without creating a new wallet.

To purchase a ship navigate to the marketplace and choose which ship you want to buy. you can choose to either use USDC or Atlas which will need to be purchased on another platform like Radium or Orca. Buying buy order section could result in the transaction being stuck as an open order. This is because when you buy from this section you are choosing the price youd like to pay. When you purchase from the sell order section, you are agreeing to the price the seller wishes to sell their ship for.

If your your transaction is an open order it will remain that way until it is either filled or you cancel it. if you dont see your order on the Star Atlas site go to Step finance, find and cancel the open order, then claim your atlas.

To enlist the ships in your inventory navigate to the faction fleet and select the ships you wish to enlist. Each type of ship enlisted will have their own fleets. Click on the button that says ship enlistment and you will see available ships to be enlisted. Click on the enlist fleet button and your ships will be staked. Depending on the size of ship the resupply time and cost will vary. Atlas accrued from enlisting ships can be collected at any time.

To withdraw enlisted ships the entire fleet must be fully stocked with resources and be completely repaired. You cannot withdraw just one ship at a time.