Let me suggest some ideas, applications, and resources.
Hands can be posed on a character either by clicking on each individual finger joint or by using the Sub Tool Detail menu, Pose. Manga Perspective allows you to configure a manga-like perspective with the depth emphasized when editing a 3D drawing figure. You can also change the light source, the body shape of the 3D drawing figure, the camera angle, etc.
Alternatively, you could drag and drop one of the four default 3D Characters (there are two school boys and two school girls) into your scene: All materials, 3D, Character.
First, create your drawing. Then go into the layer menu and select Alpha Lock. From now on, any details you add will stay within the boundaries of your layer. In other words, you won’t color outside the lines or pixels of your original drawing. Clipping mask is quite similar. First, you create your drawing. Second, add a new layer and select “clipping mask.” The base layer will then become a mask and you won’t color outside the lines of your original shape.
Many artists use 3D models for drawing faster and easier: Maya, Character Creator, Poser, and VRoid Studio (it is a free application to create 3D models of humanoid avatars).
YouTube channels: Art for Kids Hub, Mark Crilley, Proko, Jazza, and Circle Line Art School.
More resources: DragoArt.com, How To Draw it, Drawing Now, Drawing Coach, drawspace, Drawn in Black, How to Draw Cartoons Online!, eHow, HTDFC, and wikiHow, Drawing.
Royalty free photos, illustrations, and vector graphics: Pixabay and WPClipart
Art Pose Apps: MagicPoser is one of the best tools for character posing and art reference. An alternative is ArtPose. It is a fun and artistic app for posing the male and female figure. It allows you to create poses in minutes.