Creating a Roku channel can be a daunting task, even when going the direct publisher route which simplifies channel creation somewhat.
Here is a list of things that you need to be able to get started creating a channel for Roku Direct publisher.
1) Video Host
for your video content. As you mentioned you have Vimeo, but unless it is Vimeo Pro ($240/annually) or better it will not work as a host.
2) Graphic Artwork
images as part of the branding for your channel which include: Channel Poster, Channel Logo, Splash Screen and Small Logo for Roku Search.
You can use websites like www.befunky.com or www.canva.com to edit/create those images or download a program like Inkscape
3) MRSS/JSON feed
- this will be the hardest part.
Currently the best options that are available are:
- ROKU JSON feed manager
$64.95 (one time purchase)
- JWPlayer does offer video hosting as well as MRSS/JSON support for $120/annually for 500 videos / 50k plays. Note: ODD Networks that KJ referenced in his link doesn't work currently. The CEO mentioned they are reworking the free version, but I would not count on that anytime soon.
All of these things above come with a bit of a learning curve, and some kind of price, but will allow you to build a decent channel.
I would be glad to help you with any questions, and can even help with creating graphics if you need it.