New noob question

I have started to use Blender but I still have to learn many basics things. I don’t understand how to elongate some object. I’m doing tutorial about dolphin but I can’t advance until I figure that out. Thanks for help!

By elongate you mean scale? Because you can either use the scale tool hotkey is “S” (and if you want to restrain it to an axis tap X, Y or Z after S) of course you have the select the vertices you want to scale. Or you can just grab them “B” for box select and then “G” for grab of just use the arrow things.

Or maybe E for extrude, which creates new geometry attached to your selection.

were you following the tutorial with the lattice modifier? here is a link to the lattice modifier manual.