Your first route
Your first route
You need a stock Workbench, iron and copper. Slipstream adds its own Pipe Workbench; it does not need a generator or fuel.
1. Make the workbench
At the standard Workbench, craft a Pipe Workbench using 6 Iron Ingots and 4 Copper Ingots. Place it and press F to open it.

Choose a colour tab, then a tube shape. Every colour uses the same recipe costs.
2. Connect two stops
Craft two suckers and enough tubes to connect them. The elbow stations have a downward mouth and a sideways route port. A Straight Sucker Station has a downward mouth and an upward port.
Hang each mouth two blocks above a solid standing surface, leaving room for a full-size player beneath it. Connect the route openings using straights, corners, rising or descending elbows and verticals. Each part fits within one block.

Match adjacent openings. Other blocks can surround the tube, but the bore and the standing area beneath each mouth must stay clear.
Aim at an existing tube to extend it. Parts snap to matching neighbouring ports; use R to choose another placement rotation. Colours connect to each other.
3. Name it and ride
Placing a sucker opens its name field. Press F on it later to rename it. Names and connections are saved with the world; the builder controls naming and dismantling.
Walk beneath the mouth to board automatically. You shrink smoothly before lifting, travel in first person facing the route, then grow back at the destination. Your skin and outfit stay with you. WASD is locked until you return to full size.
Step at least 1.5 blocks clear before boarding again. Crouch or use /stabort to request a safe return.
4. Add a third destination
Connect another sucker through a Tube Splitter. When several stops are reachable, approaching the intake opens the destination chooser.

Choose a stop to depart. Cancel leaves you at the entrance; step away before approaching again.