You’re welcome to use those boards labeled “solderable protoboards” (or similar, can’t remember exactly) for practice.
In general, anything on those wire shelves you can use to mess with them buy your own. Those protoboards are an exception; they’re yours to take, like small parts in the wall drawers. Just be mindful of using only what you need.
Also, for soldering practice, you might prefer purpose-made kits. They’re inexpensive and are actually working circuits, so they can be more helpful for picking up circuit building skills.