When a model opens, you'll first see the full-size minimap. This lets you pick your starting point before you start walking around. Tap anywhere on the map to jump there, or close the map to start from where the orange dot is.
Reading the minimap
After you close the full-size map, a smaller version stays in the top right corner. The orange dot shows where you are, and the cone shows which direction you're facing.
Jumping to a new spot
To open the full-size map again, tap the expand icon in the corner of the small minimap. From there you can:
Tap anywhere to jump to that spot.
Tap and hold to fine-tune your exact position before you land.
Pinch to zoom in or out on the map.
To close the map, tap the X in its top-left corner. While the full-size map is open, it's the only close button on screen. The back arrow is hidden, so you won't accidentally leave the model.
Tips
The orange dot and cone always match where you are and which way you're facing.
To jump to a spot you can already see, double-tap it in the model instead of opening the map. See Moving Around a Model in Resolve Field.