Are you familiar with some backend development , api,webhooks and database? There are some technologys for these. For backend I suggest learning 'php' and 'mysql' for database and read a couple articles about 'api' and 'http protocol'. If u have time learn a little about html,css & JavaScript then u r ready to build bots. When you finish learning those read this (its the documentation for there api). PS: you won't understand anything in this documentation if u don't well know things listed above! https://core.telegram.org/bots/api&grqid=ikCOiRqH&s=1&hl=en-ET