customize my script

Dear Forum members,
I am new in codeigniter and recently I parches a script form internet,  I am looking for same changes on it can you please let me know  how to customize it The link is **deleted**
What I am looking to updates:
•        Add Russian language (as default)
•        Add RTL or Persian language support
•        Add languages selector button on header
•        Add yandex map or 2gis map Instead google map
•        Add local payment gateway (which is phone payment) instead paypal
•        Add custom font for both RTL and LTR languages

Regards
Sarbaland