Starting Tips towards a Sheet for an RPG Character Progression

Hi, sorry for where I may be going astray here but I’m really just looking for some starting tips on creating a sheet for a very specific area with an RPG Character. I understand fully if it’s recommended to find an existing tutorial but if that’s the case I’d appreciate directions to one that is a bit more on point for what I want.

What I want to do is create a sheet that adds up Skills from Skill Points and various Bonuses over 20 levels. I haven’t really thought of what to include besides the levels going down in rows, and the 8 Skills. Actually, it probably makes more sense to have the levels in the column section and the skills descending the rows. Though I’m still confused on how to add in the non level bonuses. I don’t *think* I’ll want more than your basic addition formula. But for the gamers that have gone this far or further before, I absolutely appreciate suggestions.