Notation in transistor circuits
The arrows toward a marked voltage indicate a connection (that is not shown) to a voltage rail. It is typical in modern schematics to show positive voltages at the top and negative voltages at the bottom. Very simple.
In the second case, the duplicated arrows are assumed to be connected to the same voltage source since no others are shown. If there were two in the same schematic they should all be individually labeled (or somehow grouped) in order to avoid any ambiguity.
The arrows shown with the current name beside them indicate the name assigned to that current and also the assumed direction of the current. If the value turns out to be negative, then the current is flowing in the opposite direction of the arrow.