Two essential tools :
The first one is a layer type : the CTG Layer. This acronym means Colors and Textures Generator.
Thanks to this layer, it's easier to colorize your images, but you can only colorize them. The Drawing tools will indeed be inaccessible, and the Main Panel's options will be limited. Some options on the Timeline will be restrained, but new ones will appear.
Rest assued, it is possible to Transform a CTG Layer in an Anim Layer at any time (by selecting the option in the Layer menu or by a right click on the layer). You can also go back to a CTG Layer if needed.
The other compoment of this tool is the Speedfill, also called Squiggles. You will need to draw a stroke on the area to fill for the color to spread to the delimiting outlines.
This virtual stroke will let you fill all of your color area at once, without the need to Fill inside or to use the Light Table.
It is represented by a pixel checkerboard to show their invisibility in the final rendering.
The first rule of the Speedfill is : the larger Squiggle always wins ! This "competition" between Squiggles is very important to know to understand how they work.
Squiggles look like a checkboard which you can change the transparency. In the Windows > Show > Display Settings menu, in the last section, you can change the value of the pixels in the numeric fields of the mini-sliders adjacent to the Squiggles values : 10 and -10% by default.