Hi @clivealb
First thing you should do is become a member of MSP/PAL community.
Please do follow below link to get more details on the same.
https://steemit.com/mspsteem/@pritpatel/how-to-discord-with-pal-discord-channel.
Next thing is to keep a eye on the @minnowsupport account.
Every week there will a announcement of the contest via blog post in contest category.
Only thing you have to do is post your post link as a comment in the announcement post.
Please do read the all details described in the post.
Here is a previous link of how the post looks like.
Please do let me know if you need more information.