Again, you can find almost every topic possible on telegram. From fast cars to cryptocurrencies and cute animal images.

Choose a channel that interests you and press the join button. Your phone should open the channel in your Telegram app automatically. Now press join inside the app and congratulation, you're a part of this channel.

You can copy the name of the that looks like this: @name_of_the_channel and search for it without the @ symbol on the telegram Search box on your Telegram app. This should work both in the mobile and desktop versions. Good luck.