How do i change the modifier from dex and str to con to achieve this? thank you

"At 3rd level, you have learned to use your body weight to empower your strikes. You may use your Constitution modifier in place of Dexterity modifier when calculating your Unarmored Defense and for the both the attack and damage rolls for any Martial Arts attacks. Additionally, as a reaction you can spend a ki point to grant yourself advantage on Strength (Athletics) checks to resist being grappled or moved against your will. "

Subclasses & Races FAQ #s 8 & 9: (https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/131411-a-homebrewers-how-to-faq)

dang so ill have to manually do the CON math for attack and damage. ok thank you for all the info!!

You could use a snippet and/or an Action, but it won’t include any magic bonuses from the weapon(a).

thanks again