There are multiple ways of doing this told below:
Box select: press the B key and you can click and drag a square that will select everything inside.
Circle select: press the C key, and your mouse will change to a circle, anything clicked inside the circle will be selected.(You can scroll your mouse wheel in and out to change the size of the circle.)
Holding shift: You can manually select vertices while holding Shift down to keep the previous selections as well.
- With one vertex selected of an object and pressing Ctrl+L, you will select the whole object itself that is part of that one vertice you selected at the start.
- Pressing L with your mouse over geometry will select all geometry connected to the element below your cursor.
Then you can use the transformation manipulators (using arrows on the screen) or press the G while selected to move it as well.
How do I hide objects
“/” on the numpad will hide all but the selected object, and zoom into it for editing.
“H” and “alt H” are used to hide and show at the object level. Shift H” hides non selected items.
This also works in edit mode with verts/edges/faces.
Also don’t forget the layers system for objects.
Under the help menu there’s a hotkey list with a search function.