Basic rules
Here's a link to
5e's basic rules. Part 1 details character creation, but give me a shout if anything is unclear.
Ability scores
Use the standard array of
15, 14, 13, 12, 10, 8 or point buy.
Here's a point buy calculator:
https://chicken-dinner.com/5e/5e-point-buy.html
Race/heritage
Tasha's has relaxed the rules on race. If you don't have Tasha's then you can read about the changes here:
AL supplement - Appendix 1.
Basically, you can apply the ability bonuses wherever you want and swap out proficiencies/skills. Nobody is stopping you from creating a stereotypically tough 'n' gruff dwarf, but Tasha's gives you other options too.
Background
There's no problem with swapping skills and proficiencies - it's in the PHB. So pick the background that suits your character rather than the one that gives you the proficiencies you want.
PHB says:
You might want to tweak some of the features of a background so it better fits your character or the campaign setting. To customize a background, you can replace one feature with any other one, choose any two skills, and choose a total of two tool proficiencies or languages from the sample backgrounds.
Here's a
guide to manually filling out your Gamers' Plane DnD 5e sheet.
Alternatively, if you create your character on DnD beyond then you can use their step-by-step character creation utilities. A lot of stuff is hidden behind a paywall unless you're in a campaign, so I'd recommend:
Creating an empty DnD Beyond character
PM me a message so I can add the character to the campaign
Finish customising your character
Install and use the chrome extension to
import the character from DnD Beyond into your Gamers' Plane character sheet.