how do i start my own podcast and upload to apple podcast

Apple has a lot of information posted at https://podcasters.apple.com.

Essentially, you'll need to upload your podcast audio file to a server. Then, you need to update a RSS feed that is linked to the Apple podcast directory. Apple will use this file to point people to your server to download your episodes.

Pleae read my 'get you started' page on podcasting:

http://wilmut.uk/pc

and do come back if you have any queries. Note that the Apple help page linked to above is specifically aimed at 'premium podcasters' who want to charge listeners, which I doubt is what you want to do. Most people make podcasts which are free.