How Does Digital Art Work - Tumblr Posts

YALL 

so this is a rough sketch of my two characters from my displaced  story!! yohoo alexa and elijah :-D

BUT I HAVE NO IDEA HOW TO DO DIGITAL ART HELP MEe. im a fine artist irl but i have no experience drawing on my wacom and i want to practice so any tips would be so appreciated!! help me dear god this is so hard  also i need some recommendations for free drawing programs (i used to have photoshop but the subscription got too expensive rip im a poor college student) 

anyways thank youu for reading i hope it looks ok so far!!