How to download a certificate for Telegram BOTA to work?

Question

PHP

Please tell me I can't figure it out.
I received a public key from the hoster, put it on ftp.
I use the function: setWebhook
It has 2 parameters: 1 is the address of the script, the 2nd is the certificate.
Here I have an example with only the 1st parameter:

https://api.telegram.org/bot<ВАШ_token>/setWebhook?url=<ВАШ_URl>

And I don’t understand how to pass the second certificate parameter.
There is a note on the Telegram website: https://core.telegram.org/bots/faq#i-39m-having-pr...
That, they say, "It is necessary to load InputFile, sending the string will not work.".
If it's not difficult, can you tell me or show with an example how to transfer this certificate? Tried it in different ways and it didn't work.