The J8 system is meant to run in a way extremely kind to new players.  It deliberately circumvents the complicated rule systems of other RPGs with a combination of a stream-lined skill system and considerable number shrink.  The System-resources section of the forum has some expanded rules for those that prefer that method of learning.  For everyone else, here's the basics:

Your character has 8 attributes; 4 physical and 4 ethereal.  These are the primary drivers of your character's natural ability.  In most campaigns, you have 20 starting build points to allocate into these attributes in any way you see fit.

Everything else your character can do will be driven by their Skills.  Take a look at some of the character templates and you can see roughly how this plays out with some actual numbers.  The main thing to remember is, the better your character is at something, the harder they need to work to improve at it.  This is represented by how the amount of XP it costs to get a new skill point is equivalent to the rank that is being purchased.  Rank1 costs 1xp; Rank2 costs 2xp; Rank3 costs 3xp; etc.  So if you want your character to have Rank 4 in Swim, that costs a total of 10xp; or for that same 10xp you can be Rank1 in ten different skills.  The generalist approach is often recommended outside of 1 or 2 favorite/specialty skills.  Anything you want to learn: combat, tech, science, magic, athletics, etc is done by your selection of your skills. 

Custom skills are not only permitted but encouraged.  A spy, a theater actor, and a larper could all have points in a skill called "Acting."  They could also have more nuanced skills: Bluff (more for direct lying), Drama (for emotive context), and Character Acting (for diversity of perspectives) are flavorful ways different characters pursue their methods of acting.

When in doubt, if you have any questions, post 'em up!!