To get the merchant, you'll first need to build him a house. Start by building a 9 block (width) by 7 (height) block frame/enclosure made of wood (or any other available block). Place the wood pieces in your hot bar and place the cursor where you want to put a block.  Click or press the right trigger button on the controller to place the block. Additionally, make sure that you leave a 3 block space for a door. After making the house's frame, go back to your workbench and open your inventory to craft a wooden table, chair, a door, and enough wall pieces to cover the back of the house enclosure. Once you're done crafting these, make sure that you place them in your inventory. Go inside the house frame/enclosure and place the chair and table in your hot bar.  Select the table and place it anywhere inside the enclosure.  Then equip the chairs in your hot bar and place them at the ends of the table. Place the wall pieces in your hot bar and equip them.  Then place the cursor on an area behind the enclosure and click or press the right trigger to place a piece of wall.  Repeat until you cover the entire back of the house. After building the house, go outside and look for slimes. Use your sword to kill as many as you can and then collect the gels that they drop after they die.  Slimes are found in all biomes and will spawn during the day. Other than the sword, you can also use your axe and pickaxe to kill these monsters since they're fairly weak. You're usually going to find a couple of slimes in the area where you spawn for the first time in your world. Once you've accumulated to 10 to 15 gel, you can then go back to your workbench. Open up your inventory and craft as many torches as you possibly can. Place the torches in the hot bar and equip them.  Then go inside the house enclosure and place the cursor where you want to place the torch.  Click or press the right trigger button to place the torch.[Image:Fish in Terraria Step 9.jpg|center]] Go ahead and make another 5 of these houses to accommodate other NPCs. Although the only NPC required for fishing is the merchant, you're still going to need the others to access advanced crafting and healing features as well as weapons. Making their houses in advance will save you time later on in the game. Coins are not only dropped by killing monsters but also when you break jars as well as by opening chests found all over the world. You'll need to get 50 coins in your inventory before the Merchant NPC will spawn in your world and take shelter in one of the houses that you built. The 50 silver coin requirement will only work for the merchant. Other NPCs have their own requirements and will usually spawn once you defeat bosses or have certain items in your inventory.

Summary:
Build the frame of a house. Craft a wooden door, chair, table, and walls. Place the furniture in the house. Places walls inside the house enclosure. Kill some slimes. Craft a torch. Light up the house. Continue to make houses for other NPCs, if you want. Accumulate at least 50 silver coins.