how to run a contest here for the best crypto educational roadmap & how much should the prize be
you need to clearly define the requirements and your expectations from the contest participants. Add some rules, what is acceptable and what is not. For example, plagiarism in any form is undesirable.
If you really mean crypto educational, I would advise you to do a little research on it, it is very possible that there is something similar.
as for the prize, it certainly depends on your budget, but you should keep in mind that a small prize will not attract participants with quality proposals. few will bother if the reward is miserable or negligible.
after that, you can start a contest campaign for example in
Services section if you plan to payout winners in BTC. probably the best choice and a campaign paid in BTC is always more attractive.