Can't select bones in weightpaint mode I watched a lot of tutorials but I don't know what to do further.

When I go into weightpaint mode it looks lie in the picture or the bone have an orange outline.

I tried to select the bone by right clicking, left clicking with ctrl and shift. I even tried to select the bone by name.

But it doesn't work.
The easiest way to change "bone" during weight paint is to select the corresponding vertex group.