The Mission Map in Chronicle X is made up of Map Tiles which each has a grid of five by five Squares on it. Some of those Squares have a highlight colour, and the ones that are highlighted in yellow (and has an arrow icon on them) are potential deployment spaces, where either the Hero Players or the Overmind Player can place their Models (or Blip Tokens, in the Overmind Player's case).
Note: which of the Yellow Squares that are actually deployment spaces is chosen at the start of the Mission. After that, the other Yellow Squares can usually not be used for deployment, although they can still be used by some abilities that specifically refer to Yellow Squares.
Deployment
CLARIFICATION FROM ARCHON REGARDING DEPLOYMENT: The Hero Players select two Yellow Squares (Deployment Squares) and place one Hero in each. Then, they place the remaining Heroes in squares Adjacent to the Heroes placed first, split as evenly as possible (Heroes on a Large Base only must occupy at least one such Square). Then, the Overmind Player selects two Yellow Squares (Deployment Squares), however they may place their Blip Tokens any way they like within 2 Squares of the chosen Yellow Squares. They many not select Yellow Squares that are on Tiles adjacent to Tiles that contain the Hero Players' Yellow Squares.Keep in mind however, that some Missions in the Mission Book may instruct you to perform a different deployment; where such is the case, the Mission Book’s instructions must be followed.Disregard the image (on page 12) -- it shows incorrect deployment.