I am using QGIS 3.2 Bonn and have a lot stuff imported from Google Earth.
Am I able to create a group of all drainages and label them with one click, or do I need to choose/select a new one each time?
If your drainages are all in one layer, you can label them all at once. If not, you can label one according to your needs, then save that style as a qml (button is on the lower left in the
style-tab of the layers properties) and load it for all the other layers.