The character creation process is intended to be relatively simple, but you may need help from some wikis to figure out your stats. My personal go-to is Pokémon Database. You pick a class and a species, then fill out your sheet according to the information found on this site, as well as on Pokémon Database (or whatever wiki you prefer).
The character sheet is split into a few sections. There are your Stats- in the video games, these are what determine how combat goes, and the same goes for here. Stats include HP, Defense, Special Defense, Attack, Special Attack, and Speed. Below your stats are your skills. These skills determine the outcome of things outside of combat, via skill checks. Aptitude in each skill category raises according to your class and level, and aptitude in individual skills can be increased via proficiency and practice. Feats are special abilities that are used via your Action Dice. This page goes into more detail on how Feats and Action Dice are used. Moves are exactly what they sound like- moves, from the main series pokémon games. All of the moves you know are usable outside of combat, but in combat, sets of four moves called Stances determine what moves you can use. This page goes into more detail on how moves and Stances work. Finally, the bit at the top gives you information at a glance. Your character's name, pronouns, species, level, class, type(s), and how much exp you need until your next level.
Stats determine the outcome of combat. Your HP, Defense, and Special Defense stats all determine how much damage you can take before being knocked out (or even killed). Your Attack and Special Attack stats add damage modifiers to your moves, depending on whether the move is physical or special. Your Speed stat determines how far you can move on a combat turn, as well as when you go in the turn order.
Your initial base stats are your species' base stats as seen in the pokémon video games, divided by 10 and rounded up. For example, if your video game Attack stat is any number from 41 to 50, your initial base stat for Attack is 5. From here, you figure out your EVs. EVs allow you to customize your base stats, to an extent. You may subtract up to two points from any of your stats, and using those points that you subtracted, add up to two points to any of your other stats. You write your EVs into the small spaces below the main boxes for your base stats, and you write your base stats (your species base stats, plus your EVs) in the main box.
Your leveled stats are your base stats multiplied by your level. At level 1, these are equal to your base stats. Most of these are only used to find your modifiers, but Speed has an additional purpose- your leveled Speed stat is your reaction time- this number determines what the turn order is. The higher the number, the earlier your turn.
Your modifiers are the section of the sheet you use in combat! The HP modifier determines your overall hit points, and is your leveled stat multiplied by three. The Defense and Special Defense modifiers determine the hit points of your barriers- smaller health pools that are taken from before your HP gets taken from. These modifiers are found by multiplying your leveled stat by two. Your Attack and Special Attack modifiers are additional damage that gets added to your moves. Physical moves use your Attack modifier, and Special moves use your Special Attack modifier. These modifiers are found by dividing your leveled stat by 10, and rounding to the nearest number. Your Speed modifier determines how many meters (hexes) you can move in a combat turn. The default amount of hexes that can be moved in a combat turn is 3, so your speed modifier is added to 3 to find how many hexes you can move in a turn. It is found the same way as your Attack modifiers.
The sections to the right of the modifiers concern stat stages. Stat stages are raised or lowered by certain moves and feats, and can be raised or lowered up to three times in each direction. Accuracy modifies the accuracy of your attacks by adding or subtracting 10% for the first stage, 20% for the second stage, and 50% for the third stage. Your defense stats are healed by 20% of their maximum capacity for each raise in your defense stat, and damaged equally for each lower of your defense stat. The box to the right is for writing in the number that 20% of your defense stat would be. Your attack modifiers get raised or lowered by 2 for the first stage, 5 for the second stage, and 5 plus your level for the third stage. Speed is a little strange, compared to the rest. Once you gain three stat stages in speed, you either gain an extra turn action in your next turn or lose your turn action in your next turn, depending on whether the stages were positive or negative. You may still move and use Action Dice on a turn on which you can't use a turn action.
The next steps are altered by your class, so more information can be found on each class' dedicated page. Choose wisely!