This all probably seems insultingly simple so far, but do not be led into skimming. Things will get more complicated soon. Also, do not try a new command until you are told it is time to. Otherwise, you may make Info skip past an important warning that was coming up. This is a big node and it does not all fit on your display screen.
Space moves forward, to show what was below the bottom of the screen.
When you type the space, the two lines that were at the bottom of the screen appear at the top, followed by more lines. Delete takes the two lines from the top and moves them to the bottom, usually , but if there are not a full screen's worth of lines above them they may not make it all the way to the bottom. Space and Delete scroll through all the nodes in an Info file as a single logical sequence. In this sequence, a node's subnodes appear following their parent. If a node's menu is on the screen, Space takes you into the subnodes listed in the menu, one by one.